Answer:
HCl < CH₃COOH < NH₃ < NaOH
Explanation:
Given compounds:
Acetic acid: CH₃COOH
Ammonia; NH₃
Hydrochloric acid: HCl
Sodium hydroxide: NaOH
All the solutions are of the same molarity which is 0.1M. We need to see how these compounds dissociate to form solutions in order to establish their pH value:
For Acetic acid;
CH₃COOH + H₂O ⇄ H₃O⁺ + CH₃COO⁻
Acetic acid is a weak acid and it ionizes slightly in solutions. It would have a pH close to 7
For Ammonia;
NH₃ + H₂O ⇄ NH₄⁺ + OH⁻
Ammonia is a weak base and it ionizes slightly in solutions. It sets up an equilibrium in the process. It's would be slightly above 7
For HCl:
HCl + H₂O → H₃O⁺ + Cl⁻
HCl is a strong acid and ionizes completely in solutions. It has a very low pH
For NaOH:
NaOH → Na⁺ + OH⁻
NaOH ionizes also completely in solutions and it breaks down into sodium and hydroxide ions. It is a strong base and it would have a high PH value.
HCl < CH₃COOH < NH₃ < NaOH
This is the trend of increasing pH
Answer:
Explanation:hi
3.5 mg of optically-enriched (-) sugar P was dissolved in 1.00 mL methanol in a 1.00 mL volumetric flask. The optical rotation was found to be (-)0.022° in a 5.0 cm cell. What is the specific rotation? (1 points) Show all your work
Specific rotation of a liquids can be determined from concentration, length of column and its optical rotation. The specific rotation of the solution in 5 cm length column and 3.5 g in 1 mL is -12.57°.
What is optical rotation?Optical rotation of a solution is the angle of rotation of a plane polarized light which passes through the solution. If the solution is in 1 decimeter column with 1g/l of concentration then it is called specific rotation.
The plane polarized light have orientation to either one direction left or right. The plane polarized light to left is leavo and that of right is called dextro.
The equation for specific rotation using density in g/ml and length of column in decimeter is as shown below:
specific rotation = [tex]\frac{\alpha }{d \times l}[/tex]
Where, l is the column length and d is density, alpha is the optical rotation.
Apply thr given values to the above equation.
5 cm = 0.5 decimeter.
specific rotation = - 0.022 /(0.5 × 3.5/1 ml)
= -12.57°.
Hence, the specific rotation of the solution in 5 cm length column and 3.5 g in 1 mL with an optical rotation of -0.022 is -12.57°.
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A unit of heat energy that was formerly used frequently was the calorie. Look up the definition of the calorie in your textbook or a handbook and record it here. Calculate the calorimeter constant for your calorimeter in cal/°C .
Answer and Explanation:
Calorie is the unit of heat energy . There are 2 units with the same name 'calorie' which is widely used.
'The amount of heat energy required to increase the temperature of 1 gram of water by mass by [tex]1^{\circ}C[/tex] or 1 K is known as small calorie or gram calorie'.
Another one is large calorie which can be defined as :
'The amount of heat energy required to make arise in temperature of water 1 kg by mass by [tex]1^{\circ}C[/tex] or 1 K is known as large calorie or kilcalorie and is represented as Cal or kcal'.
After the adoption of SI system, thee units of the metric system cal, C or kilocal are considered deprecated or obsolete with the SI unit for heat energy as 'joule or J'
1 cal = 4.184 J
1C or 1 kilocal = 4184 J
Calorimeter constant:
Calorimeter constant, represented as '[tex]C_{cal}[/tex]' is used to quantify the heat capacity or the amount of heat of a calorimeter.
It can be calculated by ther given formula:
[tex]{\displaystyle C_{cal}}={\frac {\Delta {H}}{\Delta {T}}}}}[/tex]
where,
[tex]{\Delta {T}}[/tex] = corresponding temperature change
[tex] {\Delta {H}[/tex] = enthalpy change
Its unit is J/K or J/1^{\circ}C[/tex] which can be convertyed to cal/1^{\circ}C[/tex] by dividing the calorimeter constant by 4.184 or 4184 accordingly.
A calorie is the amount of heat energy required to raise the temperature of one gram of water by one degree Celsius, equating to 4.184 Joules. The calorimeter constant is the heat capacity of the calorimeter, calculated by dividing the amount of heat absorbed by the temperature increase during a calorimetry experiment.
Explanation:A calorie is a conventional unit of heat, defined as the quantity of heat energy required to raise the temperature of one gram of water by one degree Celsius. This definition of a calorie aligns specifically to the temperature change from 14.5°C to 15.5°C.To convert calories into Joules, the SI unit of heat, a constant of 4.184 Joules equals one calorie.
The calorimeter constant (also known as the heat capacity of the calorimeter) is vital in calorimetry, the process of measuring heat energy changes in a chemical system. It is specified in units of cal/°C. To calculate the calorimeter constant for your calorimeter, you would have to know the mass of the calorimeter and the temperature change observed during an experiment. The constant is calculated by dividing the amount of heat absorbed (in calories, calculated using known quantities and specific heat values of substances involved) by the temperature increase.
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A 40.15 gram sample of a hydrate of Na2SO4 was heated thoroughly in a porcelain crucible, until its weight remained constant. After heating, 21.27 grams of the anhydrous compound remained. What is the formula of the hydrate?
Answer:
The formula of the hydrate of the sodium sulfate is :[tex]Na_2SO_4.7H_2O[/tex]
Explanation:
Mass of hydrated sodium sulfate = 40.15 gram
Mass of completely dehydrated sodium sulfate = 21.27 gram
Mass of water molecules present in hydrated sodium sulfate =x
40.15 gram = 21.27 gram + x (Law of conservation of mass)
x = 40.15 gram - 21.27 gram = 18.88 g
Moles of water = [tex] \frac{18.88 g}{18 g/mol}= 1.04mol[/tex]
Moles of sodium sulfate =[tex]\frac{21.27 g}{142.04 g/mol}=0.1497 mol[/tex]
Whole number ratio of sodium sulfate and water:
Sodium sulfate =[tex]\frac{0.1497 mol}{0.1497 mol}=1[/tex]
Water =[tex]\frac{1.04 mol}{0.1497 mol}=6.9 a\\rox 7[/tex]
The formula of hydrate be [tex]Na_2SO_4.7H_2O[/tex]
So, the formula of the hydrate of the sodium sulfate is :[tex]Na_2SO_4.7H_2O[/tex]
The formula of the hydrate, the mass of water lost is calculated by subtracting the mass of anhydrous Na₂SO₄ from the original hydrate mass. The number of moles of each substance is then calculated and the ratio of moles of water to moles of Na₂SO₄ is approximately 7, giving a hydrate formula of Na₂SO₄·7H₂O.
The formula of the hydrate of Na₂SO₄, we first determine the mass of the water lost during heating by subtracting the mass of the anhydrous Na₂SO₄ from the original mass of the hydrate:
Mass of water lost = original mass - mass of anhydrous Na₂SO₄
Mass of water lost = 40.15 grams - 21.27 grams = 18.88 grams
Now, to find the number of moles of Na₂SO₄ and H₂O, we use their molar masses (Na₂SO₄ = 142.04 g/mol, H₂O = 18.01 g/mol):
Moles of Na₂SO₄ = 21.27 grams / 142.04 g/mol = 0.1498 moles
Moles of H₂O = 18.88 grams / 18.01 g/mol = 1.048 moles
The mole ratio of H₂O to Na₂SO₄ is found by dividing the moles of H₂O by the moles of Na₂SO₄:
Mole ratio = moles of H₂O / moles of Na₂SO₄
Mole ratio = 1.048 moles / 0.1498 moles ≈ 7
Therefore, the empirical hydrated compound formula is Na₂SO₄·7H₂O.
Write an equation for the reaction of solid aluminum metal with hydrochloric acid (hydrogen monochloride) dissolved in water to form aluminum chloride dissolved in water and hydrogen gas. When balanced, what is the coefficient for the hydrochloric acid (hydrogen monochloride)?
Answer:
The coefficient for the hydrochloric acid is 6.
Explanation:
Stoichiometric coefficient are the number written in front of the reactants and products in balanced chemical reaction.
When solid aluminum reacts with hydrochloric acid to give aluminum chloride and hydrogen gas.
[tex]2Al(s)+6HCl(s)\rightarrow 2AlCl_3(aq)+3H_2(g)[/tex]
The coefficient for the aluminum is 2.
The coefficient for the hydrochloric acid is 6.
The coefficient for the aluminum chloride acid is 2.
The coefficient for the hydrogen gas is 3.
Classify each of these soluble solutes as a strong electrolyte, a weak electrolyte, or a nonelectrolyte. Solutes Formula Nitric acid HNO3 Calcium hydroxide Ca(OH)2 Acetic acid H3CCOOH Methyl amine CH3NH2 Potassium chloride KCl Ethanol C2H5OH Glucose C6H12O6
Answer: Strong electrolytes:[tex](HNO_{3})[/tex] Nitric acid, [tex](Ca(OH)_{2})[/tex])Calcium Hydroxide and (KCl) potassium chloride
Weak electrolytes: [tex](CH_{3}COOH)[/tex]Acetic acid and [tex](CH_{3}NH_{2})[/tex] Methyl amine
Non-electrolytes:[tex](C_{2}H_{5}OH)[/tex]Ethanol and [tex](C_{6}H_{12}O_{6})[/tex]Glucose
Explanation: Electrolytes are those compounds which can conduct electricity when dissolved in any polar solvent.
Strong electrolytes are those compounds which completely ionise when dissolved in polar solvent and hence produce ions in solution . So greater the capacity of an compound to ionize itself greater number of ions would be present in solution and hence greater will be the capacity of the solution to conduct electricity.
Ionic compounds like [tex](HNO_{3})[/tex] Nitric acid ,(KCl) Potassium chloride and [tex](Ca(OH)_{2})[/tex])Calcium hydroxide are completely ionized when dissolved in polar solvent so these compounds are strong electrolytes.
Weak electrolytes are those compounds which undergo partial ionization when dissolve in polar solvents . So they are not able to produce more ions in the solution and hence the conductivity of a solution containing weak electrolytes is low.
[tex](CH_{3}COOH)[/tex]Acetic acid and [tex]CH_{3}NH_{2}[/tex]Methyl amine are partially ionized when dissolved in polar solvent so these electrolytes are weak electrolytes.
Non-electrolytes are those compounds which are not at all ionized in the polar solvent and they remain as molecules itself even if they are dissolved.
[tex](C_{2}H_{5}OH)[/tex]Ethanol and [tex](C_{6}H_{12}O_{6})[/tex]Glucose do not ionize when dissolved in polar solvent and remain as molecules itself so the solutions of these compounds will not have ions and hence they would be unable to conduct electricity.
so
What mass of potassium hypochlorite (FW-90.6 g/mol) must be added to 4.50 x 10 mL of water to give a solution with pH 10.20? [Ka(HCIO) 4.0 x 10-8] 0.032g ? 2.4 g 04.1 g 9.1 g 20. g
Answer : The mass of potassium hypochlorite is, 4.1 grams.
Explanation : Given,
pH = 10.20
Volume of water = [tex]4.50\times 10^2ml=0.45L[/tex]
The decomposition of KClO will be :
[tex]KClO\rightarrow K^++ClO^-[/tex]
Now the further reaction with water [tex](H_2O)[/tex] to give,
[tex]ClO^-+H_2O\rightarrow HClO+OH^-[/tex]
First we have to calculate the pOH.
[tex]pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-10.20=3.8[/tex]
Now we have to calculate the [tex]OH^-[/tex] concentration.
[tex]pOH=-\log [OH^-][/tex]
[tex]3.8=-\log [OH^-][/tex]
[tex][OH^-]=1.58\times 10^{-4}M[/tex]
Now we have to calculate the base dissociation constant.
Formula used : [tex]K_b=\frac{K_w}{K_a}[/tex]
Now put all the given values in this formula, we get :
[tex]K_b=\frac{1.0\times 10^{-14}}{4.0\times 10^{-8}}=2.5\times 10^{-7}[/tex]
Now we have to calculate the concentration of [tex]ClO^-[/tex].
The equilibrium constant expression of the reaction is:
[tex]K_b=\frac{[OH^-][HClO]}{[ClO^-]}[/tex]
As we know that, [tex][OH^-]=[HClO]=1.58\times 10^{-4}M[/tex]
[tex]2.5\times 10^{-7}=\frac{(1.58\times 10^{-4})^2}{[ClO^-]}[/tex]
[tex][ClO^-]=0.0999M[/tex]
Now we have to calculate the moles of [tex]ClO^-[/tex].
[tex]\text{Moles of }ClO^-=\text{Molarity of }ClO^-\times \text{Volume of solution}[/tex]
[tex]\text{Moles of }ClO^-=0.0999mole/L\times 0.45L=0.0449mole[/tex]
As we know that, the number of moles of [tex]ClO^-[/tex] are equal to the number of moles of KClO.
So, the number of moles of KClO = 0.0449 mole
Now we have to calculate the mass of KClO.
[tex]\text{Mass of }KClO=\text{Moles of }KClO\times \text{Molar mass of }KClO[/tex]
[tex]\text{Mass of }KClO=0.0449mole\times 90.6g/mole=4.07g\approx 4.1g[/tex]
Therefore, the mass of potassium hypochlorite is, 4.1 grams.
To find the amount of potassium hypochlorite required, we first calculate the concentration of [OH-] ions from the given pH, then use this to calculate the amount of hypochlorite ions required. Our calculations yield an approximate amount of 0.15g which, among the provided options, the closest is 0.032g.
Explanation:In this problem, we are asked to determine the mass of potassium hypochlorite that must be added to water to give a solution with a pH of 10.20. Potassium hypochlorite is a weak base, and the formula for pH is pH = 14 - pOH. Since pOH is the negative log of the concentration of OH- ions, we can rearrange to find [OH-].
First, find the pOH: pOH = 14 - pH = 14 - 10.2 = 3.8. Then find the [OH-]: [OH-] = 10^-pOH = 10^-3.8. This gives the concentration of hypochlorite ions (OCl-) in solution because in water it dissociates as KOCl -> K+ + OCl-.
Using the molar mass of potassium hypochlorite, we can find the mass that must be added. The molar mass is given as 90.6 g/mol. So to find the mass, we multiply the volume of the water (which must be in liters, so 4.5 * 10^-2 L) by the [OH-] and then by the molar mass of potassium hypochlorite. Thus, mass = volume * [OH-] * molar mass =~ 0.15g. Hence the closest answer is 0.032g.
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(C6H6) can be biodegraded by microorganism. if 30 mg of benzene is present, what amount of oxygen required for biodegradation, no new cells are formed?
Answer:
36.92 mg of oxygen required for bio-degradation.
Explanation:
[tex]5C_6H_6+15O_2\rightarrow 12CO_2+15H_2O[/tex]
Mass of benzene = 30 mg = 0.03 g (1000 mg = 1 g )
Moles benzene =[tex]\frac{0.03 g}{78 g/mol}=0.0003846 mol[/tex]
According to reaction 5 moles of benzene reacts with 15 moles of oxygen gas.
Then 0.0003846 mol of benzene will react with:
[tex]\frac{15}{5}\times 0.0003846 mol=0.0011538 mol[/tex] of oxygen gas
Mass of 0.0011538 moles of oxygen gas:
0.0011538 mol × 32 g/mol = 0.03692 g = 36.92 mg
36.92 mg of oxygen required for bio-degradation.
Which of the following definitions of pesticides in NOT correct? a. Herbicides are chemicals that kill plants. b. Insecticides are chemicals that kill insects. c. Fertilizers are chemicals that kill plants. d. Fumigants are chemicals that fungi.
Answer:
Fertilizers are chemicals that kill plants.
Explanation:
Fertilizers are not pesticides. Fertilizers helps to improve plant yield by supplying nutrients needed for plant growth and food formation. When fertilizers are applied to plants, the nutrient pool increases and plants can readily grow without any deficiency resulting from lack of one mineral or the other.
Herbicides are used to kill plants.
The four bonds of carbon tetrachloride (CCl4) are polar, but the molecule is nonpolar because the bond polarity is canceled by the symmetric tetrahedral shape. When other atoms substitute for some of the Cl atoms, the symmetry is broken and the molecule becomes polar. Rank the following molecules from the least polar to the most polar: CH2Br2, CF2Cl2, CH2F2, CH2Cl2, CBr4, CF2Br2.
Answer:The following would be the polarity order CH₂F₂>CF₂Br₂>CF₂Cl₂>CH₂Cl₂>CH₂Br₂>CBr₄.
Explanation:
The polarity of any bond is associated with its dipole moment.
Dipole moment is created when two charges having equal magnitude but opposite signs are separated by a distance. Dipole moment is a vector quantity and it has a direction.
Mathematically:
Dipole moment=Magnitude of charge×distance between the charges
The charge separation only occurs in a bond when the two atoms forming bond have different electronegativities .The atom having more electroegativity pulls the shared electron density between the bonds towards itself thereby generating partial charges on individual atoms .
The atom which pulls the shared electron density between the bonds (more electronegative atom) towards itself develops a partial negative charge and the atom (less electronegative atom) from which the electrondensity is pulled generates a partial positive charge.
This leads to the development of a dipole as partial charges with opposite signs on individual atoms are separated by the bond length and the direction of the dipole is towards the electron which withdraws the electron density.
So we can say that the molecules will only have polarity or the molecule would be polar when they have a net dipole moment.
Net dipole moment of molecule is the vector sum of individual dipole moments of individual bonds.
It is possible that individual bonds may create dipole moments but due to the overall symmetrical nature of molecule these individual bonds cancel each other and hence the net dipole moment of molecule is zero which means the molecule is non-polar.
The net dipole moment in case of CCl₄ is zero because the vector some of dipole moments created by individual bonds is zero which means the individual dipoles cancel each other leading to a net zero dipole moment.
This happens as CCl₄ has a tetrahedral structure which is very symmetric and hence the individual bonds in CCl₄ are polar on account of electronegativity difference between carbon and chlorine which leads to creation of individual dipoles but overall the net dipole moment of molecule is zero as these individual dipoles cancel each other and hence the molecular is non-polar.
So we can say that molecules would have high polarity if they have high dipole moment.
A molecule will only have high dipole moment when the charge separtion is more and magnitude of partial charges developed is also more. This would happen when there is greater electronegativity difference between the two bond forming atoms
So the following would be the polarity order of the given molecules:
CH₂F₂>CF₂Br₂>CF₂Cl₂>CH₂Cl₂>CH₂Br₂>CBr₄
CH₂F₂ has the highest electronegativity difference in between bonds(C-H&C-F) so they will generate more dipole moment and hence it would be most polar.
CF₂Br₂ has the 2nd highest electronegativity difference in between bonds(C-F&C-Br) so they will generate dipole moment and hence it would be polar but less than CH₂F₂ .
CF₂Cl₂ has the 3rd highest electronegativity difference in between bonds(C-F&C-Cl) so they will generate dipole moment and hence it would also be polar but less than CH₂F₂ &CF₂Br₂ .
CH₂Cl₂ has the 4th highest electronegativity difference in between bonds(C-H&C-Cl) so they will generate dipole moment and hence it would be polar but less than other 3 molecules .
CH₂Br₂ has the 5th highest electronegativity difference in between bonds(C-H&C-Br) so they will generate dipole moment and hence it would be the least polar of all.
CBr₄ would be non-polar in nature as the net dipole moment would be Zero.
The answer is CH₂F₂> CF₂Br₂> CF₂Cl₂> CH₂Cl₂> CH₂Br₂> CBr₄
Further ExplanationIn chemistry, polarity (or polarity) is the separation of electrical charges that leads to molecules or chemical groups that have dipole or multipole electric moments. Polar molecules must contain polar chemical bonds due to electronegativity differences between bonding atoms. Polar molecules with two or more polar bonds must have asymmetrical geometry so that the bonding moments do not cancel out. Polar molecules interact through the dipole-dipole intermolecular forces and hydrogen bonds. Polarity underlies several physical properties including surface tension, solubility, and melting and boiling points.
Polarity Classification
Bonds can be categorized as extreme - very nonpolar or very polar. Completely nonpolar bonds occur when electronegativity is identical and therefore has a zero difference. Fully polar bonds are more accurately called ionic bonds, and occur when the difference between electronegativity is large enough that one atom takes electrons from another. The terms "polar" and "nonpolar" are usually applied to covalent bonds, which are bonds where the polarity is incomplete. To determine the polarity of covalent bonds using numerical tools, the difference between atomic electronegativity is used.
The bond polarity is usually divided into three groups based on the difference in electronegativity between the two bonding atoms. According to the Pauling scale:
Nonpolar bonds generally occur when the electronegativity difference between the two atoms is less than 0.5 Polar bonds generally occur when the electronegativity difference between the two atoms is approximately between 0.5 and 2.0 Ionic bonding generally occurs when the electronegativity difference between two atoms is greater than 2.0Learn more
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Grade: College
Subject: Chemistry
keywords: Polarity
The density of water at 4ºC is 1.00 x 103 kg/m3. What is water's density at 82ºC? Assume that the water's coefficient of volume expansion is constant. Enter your answer in kg/m3, without units, to the nearest whole number.
Answer:
Density of water at [tex] T = 82^0 C , \rho = 983.308 kg/m^3 [/tex]
Explanation:
The relationship between density and temperature is shown below:
[tex] \rho_1 = \rho_0 [ 1- \beta \Delta T ][/tex]
Where,
[tex] \rho_1[/tex] is the density at temperature [tex]T_1[/tex]
[tex] \rho_0[/tex] is the density at temperature [tex]T_0[/tex]
[tex] \beta [/tex] is the coefficient of volume expansion
[tex] \Delta T [/tex] is the change in temperature which is:
[tex] \Delta T = {T_1} -{T_0} [/tex]
Given,
[tex]T_0 = 4^0 C [/tex]
[tex] \rho_0 = 1.00\times 10^3 kg/m^3 [/tex]
[tex]T_1 = 82^0 C [/tex]
[tex] \Delta T = (82 -4) ^0 C =78 ^0 C [/tex]
[tex] \rho_1 = ? [/tex]
Also,
[tex] \beta for water = 0.000214 ^0C^{-1} [/tex]
So,
[tex] \rho_1 is: [/tex]
[tex] \rho_1 = 1.00\times 10^3 kg/m^3[1 - 0.000214 ^0C^{-1} \times 78^0 C ][/tex]
[tex] \rho_1 = 983.308 kg/m^3 [/tex]
This motion is associated by mechanical means such as pumps, gravity or fans, to produce the movement of the fluid: A. Free convection B. Forced conduction C. Forced convection D. Radiation INDOORS
The reaction between potassium chlorate (KCIO,) and red phosphorus (P.) takes place when one strikes a match. The products of the reaction are tetraphosphorus decoxide and potassium chloride. If 56.0 grams of KCIO, are reacted with an excess amount of red phosphorus, how many grams of P0o and KCI can be produced? How much red phosphorus is consumed in the reaction? (15 pts) Write the balanced reaction first!
Answer: Amount of tetraphosphorus decoxide formed is 38.60g, amount of potassium chloride formed is 33.99g and amount of red phosphorus consumed in the reaction is 81.48 g.
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ....(1)
For potassium chlorate:Given mass of potassium chlorate = 56.0 g
Molar mass of potassium chlorate = 122.55 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of potassium chlorate}=\frac{56.0g}{122.55g/mol}=0.456mol[/tex]
For the given chemical reaction:
[tex]10KClO_3+12P\rightarrow 3P_4O_{10}+10KCl[/tex]
Red phosphorus is given in excess . So, it is considered as an excess reagent and potassium chlorate is considered as a limiting reagent.
For tetraphosphorus decoxide:By Stoichiometry of the reaction:
10 moles of potassium chlorate reacts with 3 moles of tetraphosphorus decoxide
So, 0.456 moles of potassium chlorate will react with = [tex]\frac{3}{10}\times 0.456=0.136moles[/tex] of tetraphosphorus decoxide
Calculating the mass of tetraphosphorus decoxide by using equation 1, we get:
Molar mass of tetraphosphorus decoxide = 283.886 g/mol
Moles of tetraphosphorus decoxide = 0.136 moles
Putting values in equation 1, we get:
[tex]0.136mol=\frac{\text{Mass of tetraphosphorus decoxide}}{283.886g/mol}\\\\\text{Mass of tetraphosphorus decoxide}=38.60g[/tex]
For potassium chloride:By Stoichiometry of the reaction:
10 moles of potassium chlorate reacts with 10 moles of potassium chloride
So, 0.456 moles of potassium chlorate will react with = [tex]\frac{10}{10}\times 0.456=0.456moles[/tex] of potassium chloride
Calculating the mass of potassium chloride by using equation 1, we get:
Molar mass of potassium chloride = 74.55 g/mol
Moles of potassium chloride = 0.456 moles
Putting values in equation 1, we get:
[tex]0.456mol=\frac{\text{Mass of potassium chloride}}{74.55g/mol}\\\\\text{Mass of potassium chloride}=33.99g[/tex]
For Red phosphorus (excess reagent)By Stoichiometry of the reaction:
10 moles of potassium chlorate reacts with 12 moles of red phosphorus.
So, 0.456 moles of potassium chlorate will react with = [tex]\frac{12}{10}\times 0.456=2.631moles[/tex] of red phosphorus
Calculating the mass of red phosphorus by using equation 1, we get:
Molar mass of red phosphorus = 30.97 g/mol
Moles of red phosphorus = 2.631 moles
Putting values in equation 1, we get:
[tex]2.631mol=\frac{\text{Mass of red phosphorus}}{30.97g/mol}\\\\\text{Mass of red phosphorus}=81.48g[/tex]
Hence, amount of tetraphosphorus decoxide formed is 38.60g, amount of potassium chloride formed is 33.99g and amount of red phosphorus consumed in the reaction is 81.48 g.
Before performing the titration of your unknown acid, your partner accidentally dilutes the sample by adding water. Consider how this error would effect the following aspects of the titration curve. Part A How would this error effect the volume of base necessary to reach the equivalence point?
Answer:
It would not affect the volume of the base needed to reach the equivalence point
Explanation:
Once the unknown acid has been prepared and placed in the conical flask ready for titration, adding water to it cannot alter how much base is needed to neutralise it. Adding water to the acid merely dilutes the acid i.e if 20 parts of acid were in say 100 parts of water now 20 parts of acid are in 300 parts of water because you added more water. You will still need the exact amount of base to neutralise the 20 particles that are still in the conical flask awaiting titration.
Adding water does not make acid particles increase or decrease, it just means the base particles will have to collide with a lot more water particles to interact with the acid particles which will slow down the reaction. So the rate of the reaction can be affected, not volume of base needed to reach equivalence point.
Ammonium chloride, NH4Cl, is a salt formed from the neutralization of the weak base ammonia, NH3, with the strong acid hydrochloric acid. Given that the value of Kb for ammonia is 1.8×10−5, what is the pH of a 0.176 M solution of ammonium chloride at 25∘C?
Answer:
The pH of a 0.176 M solution of ammonium chloride is 4.9902.
Explanation:
Given:
Kb for ammonia = 1.8×10⁻⁵
Since ammonium ions are the conjugate acid of ammonia.
Thus, Ka for ammonium ions;
Ka = Kw/Kb = 10⁻¹⁴ / 1.8×10⁻⁵ = 5.5556×10⁻¹⁰
Given concentration of Ammonium chloride (C) = 0.176 M
Thus, for weak acids,
[tex]\left[H^+ \right]=\sqrt{K_a\times C}[/tex]
[tex]\left[H^+ \right]=\sqrt{5.5556\times 10^{-10}\times 0.176}[/tex]
[tex]\left[H^+ \right]=0.9777\times 10^{-5}[/tex]
pH is:
[tex]pH\ of\ the\ solution=-log\left[H^+ \right][/tex]
[tex]pH\ of\ the\ solution=-log\left(0.9777\times 10^{-5} \right)[/tex]
pH = 4.9902
Thus,
The pH of a 0.176 M solution of ammonium chloride is 4.9902.
The pH of a 0.176 M solution of ammonium chloride at 25 degrees Celsius is 11.01, calculated by using the equilibrium equation of the hydrolysis of the ammonium ion and taking into account the neutrality of the reaction.
Explanation:The question requires calculating the pH of a 0.176 M solution of ammonium chloride (NH4Cl), which is formed from the neutralization of the weak base ammonia (NH3) by the strong acid hydrochloric acid (HCl).
To find the pH, it is necessary to find the concentration of the hydronium ion [H3O+]} in the solution. The neutrality of the reaction means that when NH3 reacts with HCl, it forms its conjugate acid NH4+, which hydrolyzed in water. The equilibrium equation for the hydrolysis NH4+ + H20 <-> NH3 + H3O+ and knowing the value of Kb for ammonia (1.8×10−5), you can calculate Ka for the ammonium ion, which helps calculate [H3O+]. Using the expression Kw = Ka x Kb, since Kw is 1.0 x 10^-14 at 25 degrees Celcius, you can find Ka = Kw / Kb, which equals 5.56 x 10^-10. Using the hydrolysis reaction equilibrium equation, Ka = [NH3][H3O+] / [NH4+], and knowing [NH4+] = 0.176M (from the problem statement), you isolate [H3O+] and find it equals 9.79 x 10^-12. Finally, using the pH=-log10[H3O+], calculate the pH to be 11.01.
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Coal can be used to generate hydrogen gas (a potential fuel) by thefollowing endothermic reaction.
C(s) + H2O (g) <==> CO(g) + H2(g)
if this reaction mixture is at equilibrium, predict whether each ofthe following will result in the formation of additional hydrogengas, the formation of less hydrogen gas, or have no effect on thequantity og hydrogen gas.
a. adding more C to the reaction mixture
b. adding more H2O to the reaction mixture
c. raising the temperature of the reaction mixture
d. increasing the volume of the reaction mixture
e. adding a catalyst to the reaction mixture
f. adding an inert gas to the reaction mixture
Answer:The statements b,c,d would lead to increased formation of more hydrogen gas and statements a, e and f would lead to unchanged hydrogen concentration
Explanation:
Lechateliers principle can be used here to determine the effect of changes observed in the system.
Lechateliers principle states that if any reaction at equilibrium is subjected to change in concentration, temperature and pressure or even in reaction conditions then the equilibrium of the reaction would shift in such a way so that it can oppose the change .
So if any disturbance is caused to a reaction at equilibrium hence the equilibrium of reaction would shift in such a way so that it can counter balance the change caused to the reaction.
The above reaction is following:
C(s)+H₂O(g)→CO(g)+H₂(g)
The enthalpy change of this reaction is positive and hence the reaction is endothermic in nature.
So the given changes would lead to the following results:
a The addition of more amount of carbon C(s) would not lead to any further formation of hydrogen because carbon is added in solid state and Hydrogen gas is in gaseous state so the equilibrium for this given reaction would only change on addition of gaseous reactants as that would only lead to change in concentration.
b Since H₂O(g) is in gaseous state and a reactant and hence the addition of H₂O(g) that is more reactant would lead to more formation of hydrogen gas according to lechatelier principle. The equilibrium would shift in such a way so that it can decrease the concentration of added H₂O(g) hence it would form H₂(g).
c Since the above reaction is endothermic in nature hence increasing the temperature of reaction would also shift the equilibrium of reaction towards more formation of H₂(g) that is in forward direction.
d When we increase the volume of reaction mixture that is we are increasing the amount of reactants hence the reaction would shift towards more formation of hydorgen gas.
e The catalyst does not change the position of equilibrium and hence no shift in position of equilibrium would be observed.So amount of hydrogen gas formed would remain unchanged.
f The addition of inert gas would not lead to any change to the reaction and equilibrium would be unaffected. Hence the formation of hydrogen gas would remain unchanged.
The study of chemicals and the bond is called chemistry. When the amount of the reactant and the product get equal is said to be equilibrium.
The correct answer is b, c, d would lead to increased formation of more hydrogen gas, and statements a, e and f would lead to unchanged hydrogen concentration.
According to the principle can be used here to determine the effect of changes observed in the system.
What is an endothermic reaction?Those reactions that require energy or temperature to complete the reaction are called endothermic reactions.The principle states that if any reaction at equilibrium is subjected to change in Concentration, Temperature, Pressure, or even in reaction conditions then the equilibrium of the reaction would shift in such a way so that it can oppose the change.So if any disturbance is caused to a reaction at equilibrium hence the equilibrium of reaction would shift in such a way so that it can counterbalance the change caused to the reaction.
The reaction is as follows:-
[tex]C(s)+H_2O(g)---->CO(g)+H_2(g)[/tex]
The enthalpy change of this reaction is positive and hence the reaction is endothermic in nature.
So the given changes would lead to the following results:
A. The addition of more amount of carbon C(s) would not lead to any further formation of hydrogen because carbon is added in solid-state. Hydrogen gas is in the gaseous state so the equilibrium for this given reaction would only change on the addition of gaseous reactants as that would only lead to a change in concentration.
B. Since H₂O(g) is in a gaseous state and a reactant and hence the addition of H₂O(g) that is more reactant would lead to more formation of hydrogen gas according to the principle. The equilibrium would shift in such a way so that it can decrease the concentration of added H₂O(g) hence it would form H₂(g).
C . Since the above reaction is endothermic in nature hence increasing the temperature of the reaction would also shift the equilibrium of reaction towards more formation of H₂(g) that is in the forward direction.
D. When we increase the volume of the reaction mixture that is we are increasing the number of reactants hence the reaction would shift towards more formation of hydrogen gas.
E. The catalyst does not change the position of equilibrium and hence no shift in the position of equilibrium would be observed. So the amount of hydrogen gas formed would remain unchanged.
F. The addition of inert gas would not lead to any change to the reaction and equilibrium would be unaffected. Hence the formation of hydrogen gas would remain unchanged.
Hence, the correct answer is mentioned above.
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Use the bond energies provided to estimate ΔH°rxn for the reaction below. C2H4(g) + H2(g) → C2H6(g) ΔH°rxn = ? Bond Bond Energy (kJ/mol) C-C 347 C-H 414 C=C 611 C≡C 837 H-H 436 A) -128 kJ B) +98 kJ C) +700 kJ D) -102 kJ E) -166 kJ
hey there!:
C2H4
1 c=c ->611
4 C-H -> 4*414=1656
=> Ha=2267 kj
H2 : H-H 436
Hb = 436
C2H6
1 C-C 347
6 C-H 6*414=2484
=> Hc=2831
H=(Ha+Hb)-Hc=2267+436-2831 = -128kj
Answer A
Answer:
[tex]\Delta H_{rxn}^o=-128kJ[/tex]
Explanation:
Hello,
In this case, the standard enthalpy of reaction could be computed via the bond energies when both broken or made as shown below:
[tex]\Delta H_{rxn}^o=\Delta H_{broken}+\Delta H_{made}[/tex]
In this manner, we infer that at the reactants for ethene, [tex]C_2H_4[/tex] a double bond between carbons is broken as well as a bond between hydrogens (such values turn out positive). Furthermore, a single bond between carbons and two single bonds between carbon and hydrogen are made (such values turn out negative), in such a way, we develop the aforesaid equation to obtain:
[tex]\Delta H_{rxn}^o=(611kJ+436kJ)+(-347kJ-2*414kJ)\\\Delta H_{rxn}^o=-128kJ[/tex]
Best regards.
The combustion of ethane (C2H6) produces carbon dioxide and steam. 2C2H6(g)+7O2(g)⟶4CO2(g)+6H2O(g) How many moles of CO2 are produced when 5.60 mol of ethane is burned in an excess of oxygen?
When 5.60 mol of ethane is burned, 11.20 mol of CO2 are produced.
Explanation:The balanced equation for the combustion of ethane (C2H6) is 2C2H6(g) + 7O2(g) ⟶ 4CO2(g) + 6H2O(g). From this equation, we can see that for every 2 moles of ethane burned, 4 moles of CO2 are produced. Therefore, to calculate how many moles of CO2 are produced when 5.60 mol of ethane is burned, we can use the ratio:
2 moles of ethane : 4 moles of CO2 = 5.60 mol of ethane : x moles of CO2
Solving for x, we find that x = (5.60 mol of ethane) x (4 moles of CO2) / (2 moles of ethane) = 11.20 mol of CO2.
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5.60 moles of ethane produce 11.20 moles of carbon dioxide when burned in excess oxygen, based on the 2:4 molar ratio from the balanced combustion equation. This demonstrates the stoichiometric calculation for the reaction. Thus, burning ethane produces twice as many moles of CO₂.
To solve this, we need to use the balanced chemical equation for the combustion of ethane:
2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(g)
This equation tells us that 2 moles of ethane produce 4 moles of carbon dioxide. Therefore, the ratio of moles of ethane to moles of carbon dioxide is 2:4, or 1:2.
If 5.60 moles of ethane (C₂H₆) are burned, we can use this ratio to find the moles of CO₂ produced:
Identify the molar ratio: 1 mole C₂H₆ → 2 moles CO₂Calculate the moles of CO₂: 5.60 moles C₂H₆ × (2 moles CO₂ / 1 mole C₂H₆) = 11.20 moles CO₂Thus, burning 5.60 moles of ethane produces 11.20 moles of carbon dioxide.
You are given a food containing 6 g protein per serving (30g), how much of the food you needto add to 100 ml solution to make a solution with 500 μg protein/ml? What is the dilution factor?
Hey there!
500 mg of protein is present in 100 mL of solvent as per the concentration 0.5 mg/mL or 500 g/mL ,
So, 250 mg (0.25 g) of serving food need to be added to 100 mL solvent in order to prepare 50 mg of protein/100 mL solution.
Dilution factor = initial amount of protein / final amount of protein
= 6 g / 0.05 g = 120
Hope this helps!
The limiting reactant determines what the actual yield is. (T/F)
Answer:
True
Explanation:
Limiting reactant - the reactant which get completely consumed in a chemical reaction , is known as the limiting reactant .
As, the concentration of limiting reactant after the completion of the reaction will be zero , hence, it is used to determine the concentration of other reactants .
For example,
for a general reaction -
A + B ---> 3C
Assuming B to be the limiting reactant ,
hence, the concentration of C and A can be determined as -
1 mol of B can give 3 mol of C and 1 mol of A is used for the reaction.
Which of the following statements about soaps and detergents is NOT true?
a.Soaps form micelles in solution.
b.The hydrophilic end has the hydrocarbon chain.
c.The hydrophobic end has the hydrocarbon chain.
d.The hydrophilic end is ionic.
Answer:
The answer is B. the hydrophilic end has the hydrocarbon chain.
Explanation:
That answer is wrong because soap and detergent form a bilayer with hydrophilic and hydrophobic ends.
the hydrophilic end interacts with polar compound such as water because that end is ionic and charged, it is composed of carbon and Oxygen and forms dipole interaction and electrostatic interactions.
the hydrophobic end is the non polar end, it is composed of carbon and hydrogen chain (Hydrocarbon) which are non-polar due to equal electronegativity between carbon and hydrogen.
that is why answer B is not true, the hydrophilic end does not have the hydrocarbon chain, the hydrocarbon chain is on the hydrophobic end.
How many iron atoms are in 0.32 mol of Fe2031? 3.9x 1023 jron atoms O 3.9 iron atoms O 6.02 x 1023 iron atoms 1.9 x 1023 iron atoms O 11x 10-24 iron atoms
Answer: [tex]3.9\times 10^{23}[/tex] iron atoms
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
[tex]1 molecule of [tex]Fe_2O_3[/tex] contains= 2 atoms of iron
[tex]1 mole of [tex]Fe_2O_3[/tex] contains=[tex]2\times 6.023\times 10^{23}=12.05\times 10^{23}[/tex] atoms of iron
thus 0.32 moles of [tex]Fe_2O_3[/tex] contains=[tex]\frac{12.05\times 10^{23}}{1}\times 0.32=3.9\times 10^{23}[/tex] atoms of iron
Thus the sample would have [tex]3.9\times 10^{23}[/tex] iron atoms.
The 1H NMR signal for bromoform (CHBr3) appears at 2065 Hz when recorded on a 300−MHz NMR spectrometer. If the spectrum was recorded on a 500−MHz instrument, what would be the chemical shift of the CHBr3 proton? Enter your answer in the provided box.
Answer:The chemical shift (δ) is 6.88ppm.
Explanation:
We have the following data :
Absorption frequency of the proton in bromoform=2065Hz
Frequency of the NMR spectrometer(instrument)=300MHz
The formula for calculating the chemical shift (δ) in PPM is:
chemical shift (δ)={[Frequency of proton(Hz) -Frequency of reference(Hz]÷Frequency of NMR spectrometer(MHz }
Using the formula for chemical shift we can calculate the value of chemical shift (δ) in ppm
chemical shift (δ) ={[2065Hz-0]÷300×10⁻⁶}
chemical shift (δ) =6.88×10⁶
chemical shift (δ)=6.88ppm for a 300MHz NMR spectrometer
The chemical shift (δ) is a ratio of frequency absorbed by proton with that of NMR spectrometer frequency hence the chemical shift value would remain same what ever NMR spectrometer frequency we use. Chemical shift basically tells us about the position of signal with respect to the reference compound of TMS(δ=0).
chemical shift (δ) is measured in
So the value of (δ) is same for any spectrometer used.
The chemical shift (δ) for a 500MHz NMR spectrometer used would also be 6.88PPM.
Alternatively since the frequency of proton absorbed is directly related to the magnetic field applied that is the frequency of NMR spectrometer hence:
Let the frequency of proton absorbed in 300MHZ=V₁=2065
Let the frequency of proton absorbed in 500MHZ=V₂=?
frequency of proton absorbed∝Applied magnetic field(Frequency of NMR spectrometer)
So V₁/V₂=[300×10⁶]/[500×10⁶]
V₂=[2065×500]÷300
V₂=3441HZ
For a 500 MHz proton the frequency of absorption would be 3441MHz
using this frequency we can calculate chemical shift (δ) using above formula:
(δ)=[3441-0]/[500×10⁻⁶]
(δ)=6.88PPM
Hence we obtain the same value of chemical shift in both the spectrometers.
This answer explains how to calculate the chemical shift of a nucleus using NMR spectroscopy when switching between different instrument frequencies.
Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool used by chemists to analyze the structure of molecules. In NMR spectroscopy, the chemical shift is a measure of the resonance frequency of a nucleus compared to a standard.
To find the chemical shift on a 500-MHz instrument, we use the formula: Chemical shift on New Instrument = (Resonance Frequency on Old Instrument) × (New Instrument Frequency) / (Old Instrument Frequency).
Plugging in the values, we get: Chemical shift = 2065 Hz × 500 MHz / 300 MHz = 3441.67 Hz.
Therefore, the chemical shift of the CHBr₃ proton on a 500-MHz NMR instrument would be 3441.67 Hz.
A quantity of 0.225 g of a metal M (molar mass = 27.0 g/mol) liberated 0.303 L of molecular hydrogen (measured at 17°C and 741 mmHg) from an excess of hydrochloric acid. Deduce from these data the corresponding equation and write formulas for the oxide and sulfate of M.
Based on the data provided, it appears that the metal M with a molar mass of 27.0 g/mol reacts with hydrochloric acid to produce hydrogen gas, indicating the metal is likely aluminum. The reaction equation would be 2Al + 6HCl → 2AlCl3 + 3H2. The oxide of aluminum is Al2O3 and the sulfate is Al2(SO4)3.
Explanation:To find the equation for the reaction of the metal M with hydrochloric acid, we should first understand the typical reaction that occurs, which is a metal reacting with an acid to produce a salt and hydrogen gas:
M + 2HCl → MCl2 + H2
Given the data, we can calculate the moles of hydrogen gas (H2):
n(H2) = PV / RT
Where P is the pressure in atmospheres (741 mmHg is equivalent to 741/760 atm), V is the volume (0.303 L), R is the gas constant (0.0821 L·atm/mol·K), and T is the temperature in Kelvin (17°C = 290 K).
Once we have the moles of H2, we can find the ratio of metal M to H2 in the reaction and then use the molar mass of M to determine how many moles of M reacted, which should be half the moles of H2 produced since the metal is likely to be in Group 1 or 2. Lastly, using the molar mass of the metal (27.0 g/mol), we can confirm the stoichiometry.
For the formulas of the oxide and sulfate of M:
Oxide of M: M2O or MO, where the subscripts depend on the valency of the metal M.Sulfate of M: M2(SO4)3 or M(SO4), again depending on valency.In summary, the molar mass given and typical valence of metals may suggest that metal M is likely aluminum (Al), hence the possible chemical reactions would be:
2Al + 6HCl → 2AlCl3 + 3H2
Formulas for aluminum compounds:
Oxide of Al: Al2O3
Sulfate of Al: Al2(SO4)3
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The metal M is aluminum (Al), and the Balanced reaction is: [tex]2\text{Al} + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2[/tex] the Oxide is: [tex]\text{Al}_2\text{O}_3[/tex], and Sulfate is [tex]\text{Al}_2(\text{SO}_4)_3[/tex].
To determine the reaction and write the formulas for the oxide and sulfate of the metal M , we first need to identify the metal and its valency based on the data provided.
1. Determine the number of moles of hydrogen gas liberated:
Using the ideal gas law, PV = nRT :
- P is the pressure in atm. To convert from mmHg to atm: [tex]P = \frac{741 \, \text{mmHg}}{760 \, \text{mmHg/atm}} = 0.974 \, \text{atm}[/tex].
- V is the volume in liters: V = 0.303 L.
- R is the ideal gas constant: R = 0.0821 L·atm/(mol·K.
- T is the temperature in Kelvin: [tex]T = 17^\circ \text{C} + 273.15 = 290.15 \, \text{K}[/tex].
Now, solve for n , the number of moles of H₂ :
[tex]n = \frac{PV}{RT} \\\\ n = \frac{(0.974 \, \text{atm})(0.303 \, \text{L})}{(0.0821 \, \text{L\ . atm/(mol\ . K)})(290.15 \, \text{K})} \\\\ n = \frac{0.295 \, \text{L\ . atm}}{23.81 \, \text{L\ . atm/mol}} \\\\ n \approx 0.0124 \, \text{mol}[/tex]
2. Determine the number of moles of metal M reacted:
Given the mass of the metal and its molar mass:
[tex]\text{Moles of metal} = \frac{\text{Mass}}{\text{Molar mass}} = \frac{0.225 \, \text{g}}{27.0 \, \text{g/mol}} = 0.00833 \, \text{mol}[/tex]
3. Determine the valency of the metal M :
From the reaction with hydrochloric acid, each mole of metal M produces hydrogen gas. The general reaction is:
[tex]M + xHCl \rightarrow MCl_x + \frac{x}{2}H_2[/tex]
Since 0.00833 moles of M produced 0.0124 moles of H₂:
[tex]0.00833 \, \text{mol} \times \frac{x}{2} = 0.0124 \, \text{mol} \\\\ x = \frac{0.0124 \times 2}{0.00833} \\\\ x \approx 2.98 \approx 3[/tex]
So, the valency of metal M is 3.
4. Write the chemical reaction:
The balanced equation for the reaction is:
[tex]2M + 6HCl \rightarrow 2MCl_3 + 3H_2[/tex]
5. Write the formulas for the oxide and sulfate of M :
- The formula for the oxide of M :
[tex]M_2O_3[/tex]
- The formula for the sulfate of M :
[tex]M_2(SO_4)_3[/tex]
Given that the metal has a valency of 3, and the molar mass of 27 g/mol corresponds to aluminum (Al), the formulas for the oxide and sulfate of M (Aluminum) are:
- Oxide: [tex]\text{Al}_2\text{O}_3[/tex]
- Sulfate: [tex]\text{Al}_2(\text{SO}_4)_3[/tex]
Thus, the metal M is aluminum (Al), and the balanced reaction, oxide, and sulfate formulas are:
- Balanced reaction:
[tex]2\text{Al} + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2[/tex]
- Oxide:
[tex]\text{Al}_2\text{O}_3[/tex]
- Sulfate:
[tex]\text{Al}_2(\text{SO}_4)_3[/tex]
Calculate the final temperature of the system: A 50.0 gram sample of water initially at 100 °C and a 100 gram sample initially at 13.7 °C are mixed. The specific heat of water is 4.184 J/g°C.
Answer:
The final temperature of the system is 42.46°C.
Explanation:
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.
[tex]q_1=-q_2[/tex]
[tex]m_1\times c\times (T_f-T_1)=-(m_2\times c\times (T_f-T_2))[/tex]
where,
c = specific heat of water= [tex]4.18J/g^oC[/tex]
[tex]m_1[/tex] = mass of water sample with 100 °C= 50.0 g
[tex]m_2[/tex] = mass of water sample with 13.7 °C= 100.0 g
[tex]T_f[/tex] = final temperature of system
[tex]T_1[/tex] = initial temperature of 50 g of water sample= [tex]100^oC[/tex]
[tex]T_2[/tex] = initial temperature of 100 g of water =[tex]13.7^oC[/tex]
Now put all the given values in the given formula, we get
[tex]50.0 g\times 4.184 J/g^oC\times (T_f-100^oC)=-(100 g\times 4.184 J/g^oC\times (T_f-13.7^oC))[/tex]
[tex]T_f=42.46^oC[/tex]
The final temperature of the system is 42.46°C.
The density of the solid phase of a substance is 0.90 g/cm3 and the density of the liquid phase is 1.0 g/cm3. A large increase in pressure will a. lower the freezing point b. raise the freezing point c. lower the boiling point d. raise the triple point e. lower the triple point
The correct answer is: b. raise the freezing point.
When pressure increases, the freezing point of a substance generally increases. This phenomenon is known as the colligative property of freezing point elevation. In a system where solid and liquid phases coexist, an increase in pressure tends to favor the denser phase.
Since the liquid phase is denser than the solid phase, an increase in pressure would promote the transition from solid to liquid, causing the freezing point to rise. This effect is commonly observed in many substances and is utilized in various applications, such as in the preservation of food through high-pressure processing.
Therefore, under increased pressure, the freezing point of the substance would be raised, making option b the correct choice.
Which of the following concerning electrolytes and the solubility rules is/are true? 1. The solubility rules apply only to ionic substances. 2. All soluble ionic compounds are considered strong electrolytes. 3. The solubility rules apply to aqueous and non-aqueous solutions.
Answer:
1. is true
Explanation:
The solubility rules apply only to salts, which are ionic compounds.
2. is false. A strong electrolyte is a salt that dissociates completely in solution. Not all salts dissociate completely. For example, a 0.36 mol·L⁻¹ solution dissociates as:
K₂SO₄ ⟶ K⁺ + KSO₄⁻ (30 %) + SO₄²⁻
Thus, K₂SO₄ does not dissociate completely into K⁺ and SO₄²⁻ ions.
3. is false. The solubility rules apply only to aqueous solutions.
The electrolytes and the solubility rules that are true include:
1. The solubility rules apply only to ionic substances. 2. All soluble ionic compounds are considered strong electrolytes. It should be noted that solubility rules only apply to the ability of ionic compounds to be able to dissolve in water. The solubility rule is important as it helps in the determination of the solubility of a particular substance before one attempts to create it.In a situation where the amount of solute is the same as the solubility, then it's saturated. Also, all soluble ionic compounds are considered strong electrolytes.In conclusion, the correct options are 1 and 2.
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The estimated heat of vaporization of diethyl ether using the Chen's rule is A. 29.7 KJ/mol B. 33.5 KJ/mol C. 26.4 KJ/mol D. 36.8 kJ/mol
Answer:
C. 26.4 kJ/mol
Explanation:
The Chen's rule for the calculation of heat of vaporization is shown below:
[tex]\Delta H_v=RT_b\left [ \frac{3.974\left ( \frac{T_b}{T_c} \right )-3.958+1.555lnP_c}{1.07-\left ( \frac{T_b}{T_c} \right )} \right ][/tex]
Where,
[tex]\Delta H_v[/tex] is the Heat of vaoprization (J/mol)
[tex]T_b[/tex] is the normal boiling point of the gas (K)
[tex]T_c[/tex] is the Critical temperature of the gas (K)
[tex]P_c[/tex] is the Critical pressure of the gas (bar)
R is the gas constant (8.314 J/Kmol)
For diethyl ether:
[tex]T_b=307.4\ K[/tex]
[tex]T_c=466.7\ K[/tex]
[tex]P_c=36.4\ bar[/tex]
Applying the above equation to find heat of vaporization as:
[tex]\Delta H_v=8.314\times307.4 \left [ \frac{3.974\left ( \frac{307.4}{466.7} \right )-3.958+1.555ln36.4}{1.07-\left ( \frac{307.4}{466.7} \right )} \right ][/tex]
[tex]\Delta H_v=26400 J/mol[/tex]
The conversion of J into kJ is shown below:
1 J = 10⁻³ kJ
Thus,
[tex]\Delta H_v=26.4 kJ/mol[/tex]
Option C is correct
Consider the following reaction at 25 °C: CaCrO4s)-Ca2*la)+CrO,2(aq) Ko 7.1 104 What are the equilibrium concentrations of Ca2 and CrO42?
Answer: The equilibrium concentration of [tex]Ca^{2+}\text{ and }CrO_4^{2-}[/tex] are 0.0266 M.
Explanation:
The chemical equation for the ionization of calcium chromate follows:
[tex]CaCrO_4\rightleftharpoons Ca^{2+}+CrO_4^{2-}[/tex]
The expression for equilibrium constant is given as:
[tex]K_c=\frac{[Ca^{2+}][CrO_4^{2-}]}{[CaCrO_4]}[/tex]
We are given:
[tex]K_c=7.1\times 10^{-4}[/tex]
The concentration of solid substances are taken to be 1. Thus, they do not appear in the equilibrium constant expression.
Let the equilibrium concentration for [tex]Ca^{2+}\text{ and }CrO_4^{2-}[/tex] be 'x'
Putting values in above equation, we get:
[tex]7.1\times 10^{-4}=x^2\\\\x=0.0266M[/tex]
Hence, the equilibrium concentration of [tex]Ca^{2+}\text{ and }CrO_4^{2-}[/tex] are 0.0266 M.
The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C2H6 (g) + 7O2 (g) → 4CO2 (g) + 6H2O (l) The value of ΔS° for this reaction is ________ J/K⋅mol. The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C2H6 (g) + 7O2 (g) 4CO2 (g) + 6H2O (l) The value of S° for this reaction is ________ J/Kmol. -151.0 +718.0 -620.1 +151.0 -718.0
Answer: The value of [tex]\Delta S^o[/tex] for the given reaction is -620.1 J/Kmol.
Explanation:
Entropy change of the reaction is defined as the difference between the total entropy change of the products and the total entropy change of the reactants.
Mathematically,
[tex]\Delta S_{rxn}=\sum [n\times S^o_{products}]-\sum [n\times S^o_{reactants}][/tex]
For the given chemical equation:
[tex]2C_2H_6(g)+7O_2(g)\rightarrow 4CO_2(g)+6H_2O(l)[/tex]
Taking the standard entropy of formation for the following:
[tex]S^o_{C_2H_6}=229.6Jmol^{-1}K^{-1}\\S^o_{CO_2}=213.6Jmol^{-1}K^{-1}\\S^o_{H_2O}=69.9Jmol^{-1}K^{-1}\\S^o_{O_2}=205Jmol^{-1}K^{-1}[/tex]
Putting values in above equation, we get:
[tex]\Delta S^o_{rxn}=[(4\times S^o_{CO_2})+(6\times S^o_{H_2O})]-[(2\times S^o_{C_2H_6})+(7\times S^o_{O_2})][/tex]
[tex]\Delta S^o=[(4\times 213.6)+(6\times 69.9)]-[(2\times 229.6)+(7\times 205)]=-620.1Jmol^{-1}K^{-1}[/tex]
Hence, the [tex]\Delta S^o[/tex] of the reaction is [tex]-620.1Jmol^{-1}K^{-1}[/tex]
The standard entropy change for the complete combustion of ethane is -620.8 J/K.mol.
What is standard entropy change?The standard entropy change is equal to the sum of the standard entropies of the products minus the sum of the standard entropies of the reactants.
Let's consider the combustion of ethane.
2 C₂H₆(g) + 7 O₂(g) → 4 CO₂(g) + 6 H₂O(l)
The standard entropy change (ΔS°) is:
ΔS° = n(products) × S°products - n(reactants) × S°reactants
where,
n is the stoichiometric coefficient.S° is the standard entropy.ΔS° = 4 × 213.74 J/mol.K + 6 × 69.91 J/mol.K - 2 × 229.60 J/mol.K - 7 × 205.14 J/mol.K = -620.8 J/K.mol
The standard entropy change for the complete combustion of ethane is -620.8 J/K.mol.
Learn more about entropy here: https://brainly.com/question/6364271
Water gas (which is is a mixture of H2 and CO) can be made by reacting red hot charcoal (C) with steam (H2O). a. Write the balanced equation for this reaction. b. Show, how can the obtained water gas itself be used as a fuel (write the balanced reactions of complete combustion of H2 and CO).
To balance chemical equations you add coefficients in front of each molecule in such a way that the number of atoms in reactants are equal with the number of the atoms in products.
a) C + H₂O → CO + H₂
the chemical equation is balanced, no need for other coefficients (it is assumed 1 in front of each molecule as a coefficient)
b) Combustion it means that the hydrogen and carbon monoxide will react with oxygen.
2 H₂ + O₂ → 2 H₂O
2 CO + O₂ → 2 CO₂
Answer: The equations are written below.
Explanation:
A balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on the product side. These equations follow law of conservation of mass.
The chemical equation for the formation of water gas follows:
[tex]C+H_2O\rightarrow H_2+CO[/tex]
The gases released are hydrogen gas and carbon monoxide gas.
Combustion reactions are defined as the reactions in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide and water.
The chemical equation for the combustion of hydrogen gas follows:
[tex]2H_2+O_2\rightarrow 2H_2O[/tex]
The chemical equation for the combustion of carbon monoxide gas follows:
[tex]2CO+O_2\rightarrow 2CO_2[/tex]
Hence, the equations are written above.