Explanation:
Ion-ion forces are defined as the forces that exist between oppositely charged ions.
Dipole-dipole interactions are defined as the forces which exist between positive end of polar molecule and negative end of another polar molecule.
Ion-dipole forces are defined as the forces that exist between a charged ion and a polar molecule.
London dispersion forces are defined as the forces that arise due to the development of temporary charges on the combining atoms of a molecule.
Hence, the given substances are classified as follows.
(a) HF - It is a covalent compound but due to the difference in electronegativity of hydrogen and fluorine there will be development of partial charges on both of them.
Hence, in a HF molecule there will be dipole-dipole forces.
(b) [tex]CH_{3}OH[/tex] - There will also be development of partial charges due to the difference in electronegativity of oxygen and hydrogen atoms.
Hence, in a [tex]CH_{3}OH[/tex] there will be dipole-dipole forces.
(c) [tex]CaCl_{2}[/tex] - It is an ionic compound. Hence, there will be partial positive charge on calcium and partial negative charge on chlorine atom.
Hence, in a [tex]CaCl_{2}[/tex] molecule there will exist ion-ion forces.
(d) [tex]FeBr_{3}[/tex] - It is an ionic compound. Hence, there will also exist ion-ion forces.
Answer:
a) (2)
b) (2)
c) (3)
d) (3)
Explanation:
The intermolecular forces are the forces that make molecules to be bond in a substance. When a solvent dissolves a solute, the molecules of the solvent and the solute will be attached by the forces. The types of forces are:
Ion-ion -> It occurs at ionic compounds, which are formed by the attraction of a cation and an anion. It's the strongest force;Dipole dipole -> It occurs at polar covalent compounds. The polarity of the molecule makes that it has partial charges. The positive charge of one molecule will be attached to the negative of the other;London dispersion -> It occurs at nonpolar covalent bonds. Partial charges are induced and the attraction happen;Hydrogen bond -> It's a kind of dipole dipole force, which is strongest, and it's formed when the hydrogen is bonded to a high electronegativity element (N, O, and F).
The bonds between substances can mix these forces. So if one is polar and the other is nonpolar, the bond will be London dipole; if both are polar, dipole dipole, if one is polar and the other is ionic ion dipole; and if one is nonpolar and the other is ionic, ion London.
Water (H2O) is a polar molecule, so the dipole must happen in all of the dissolutions.
a) HF is a polar molecule, so the bond of it and water will be dipole dipole. In both substances the hydrogen is bonded to high electronegativity elements, so its hydrogen bond! But, because there's no answer to it, we can call it dipole dipole. (2)
b) CH3OH is a polar compound, and have hydrogen bonds, but, as explained above, it'll be dipole dipole forces. (2)
c) CaCl2 is an ionic compound (cation Ca+2 and anion Cl-), thus the force will be ion dipole. (3)
d) FeBr3 is an ionic compound (cation Fe+3 and anion Br-), thus the force will be ion dipole. (3)
The benzene boiling temperature (C6H6) is 80.1ºC dissolving 36 g pentane, C5H12 at 500 g benzene increases the boiling point of the solution to 82.73ºC
A. Consider the benzene boiling point constant. Show calculations.
B. In dissolving 1.2 g of unknown solute in 50 g of benzene, a solution with a boiling point of 80.36ºC is obtained, which is the molar mass of the solute (assume that i = 1) (show calculations)
Answer:
A)Boiling point constant of benzene = 2.63°C/m
B) 242.77 g/mol is the molar mass of the solute.
Explanation:
[tex]\Delta T_b=T_b-T[/tex]
[tex]\Delta T_b=K_b\times m[/tex]
[tex]Delta T_b=iK_b\times \frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Mass of solvent in Kg}}[/tex]
where,
[tex]\Delta T_f[/tex] =Elevation in boiling point
[tex]K_b[/tex] = boiling point constant od solvent= 3.63 °C/m
1 - van't Hoff factor
m = molality
A) Mas of solvent = 500 g = 0.500 kg
T = 80.1°C ,[tex]T_b[/tex] =82.73°C
[tex]\Delta T_b=T_b-T[/tex]
[tex]\Delta T_b[/tex]= 82.73°C - 80.1°C = 2.63°C
[tex]2.63^oC=K_b\times \frac{36 g}{72 g/mol\times 0.500 kg}[/tex]
[tex]K_b=\frac{2.63^oC\times 72 g/mol\times 0.500 kg}{36 g}=2.63 ^oC/m[/tex]
Boiling point constant of benzene = 2.63°C/m
B) Mass of solute = 1.2 g
Molar mas of solute = M
Mass of solvent = 50 g= 0.050 kg
i = 1
T = 80.1°C ,[tex]T_b[/tex] =80.36°C
[tex]\Delta T_b=T_b-T[/tex]=80.36°C - 80.1°C = 0.26°C
[tex]0.26^oC=1\times K_b\times \frac{1.2 g}{M\times 0.050 kg}[/tex]
[tex]M=1\times 2.63^oC/m\times \frac{1.2 g}{0.26^oC\times 0.050 kg}[/tex]
M = 242.77 g/mol
242.77 g/mol is the molar mass of the solute.
Final answer:
The boiling point constant (Kb) of benzene was found to be 2.63°C/m using the data from part A. Using this constant and the boiling point elevation data in part B, the molar mass of the unknown solute was calculated to be 240 g/mol.
Explanation:
The subject of this question is Chemistry, focusing specifically on the boiling point elevation of solutions and the calculation of molar mass from boiling point data. The problem pertains to colligative properties of solutions, which are properties that depend on the number of particles in a solution but not their identity.
Part A: Calculating Boiling Point Elevation
To find the boiling point constant (Kb) of benzene, we use the formula for boiling point elevation, ΔTb = Kb × m, where ΔTb is the change in boiling point and m is the molality of the solution. Given that the boiling point of benzene increases from 80.1°C to 82.73°C, the elevation in boiling point is 2.63°C. Molality (m) is calculated by the number of moles of pentane divided by the mass of benzene in kilograms. The molar mass of pentane (C5H12) is 72.15 g/mol, and so 36 g corresponds to 0.5 moles. The mass of benzene is 500 g, which is 0.5 kg. Thus, m = 0.5 moles / 0.5 kg = 1 mol/kg. Using these values, we can calculate Kb: 2.63°C = Kb × 1 mol/kg, so Kb = 2.63°C/m.
Part B: Determining Molar Mass of an Unknown Solute
For part B, to find the molar mass of the solute, we first calculate the change in boiling point of benzene, which is 80.36°C - 80.1°C = 0.26°C. With the boiling point constant of benzene from Part A (Kb = 2.63°C/m), and assuming i (the van 't Hoff factor) is 1 for a non-electrolyte, we establish the molality of the solution as m = ΔTb / Kb = 0.26°C / 2.63°C/m = 0.1 mol/kg. Knowing the molality and the mass of solvent (benzene), we can now calculate the molar mass (M) of the unknown solute using the formula M = mass of solute / (molality × mass of solvent in kg). With the mass of solute as 1.2 g and the mass of solvent as 0.05 kg, M = 1.2 g / (0.1 mol/kg × 0.05 kg)= 240 g/mol.
A solution is prepared by condensing 4.00 L of a gas,
measuredat 270C and 748 mmHg pressure into 58.0g
ofbenzene. Calculate the freezing point of this solution?
Answer:
-2.3 ºC
Explanation:
Kf (benzene) = 5.12 ° C kg mol – 1
1st - We calculate the moles of condensed gas using the ideal gas equation:
n = PV / (RT)
P = 748/760 = 0.984 atm
T = 270 + 273.15 = 543.15 K
V = 4 L
R = 0.082 atm.L / mol.K
n = (0.984atm * 4L) / (0.082atm.L / K.mol * 543.15K) = 0.088 mol
Then, you calculate the molality of the solution:
m = n / kg solvent
m = 0.088 mol / 0.058 kg = 1.52mol / kg
Then you calculate the decrease in freezing point (DT)
DT = m * Kf
DT = 1.52 * 5.12 = 7.8 ° C
Knowing that the freezing point of pure benzene is 5.5 ºC, we calculate the freezing point of the solution:
T = 5.5 - 7.8 = -2.3 ºC
Explain why the properties of a polymer below the glass transition temperature are different from the same properties in the same polymer above the glass transition temperature.
Explanation:
At low temperatures (below the glass transition temperature) crystalline polymers are rigid like glass. This happens because all the polymer chains are perfectly arranged, all the polymer is in the crystalline form. On the other hand, when the temperature raises, upper the glass transition temperature, some polymer chains start to get loose and form some amorphous regions in between the crystalline regions of the polymer. This condition makes the polymer more flexible.
The trash cans distributed by the city of Mobile are approximately 4 feet tall and have a square cross section with a side of approximately 30 inches. Assuming that the trash can is rectangular, approximate its capacity: 4. a. in gallons b. in metric tons of water at 4°C
Explanation:
Length of trash cans = l = 4 feet
Breadth of trash cans = b = 4 feet
Height of trash cans = h = 30 inches = 2.5 feet
1 inches = 0.0833333 feet
Capacity of trash can = Volume of the rectangular trash can = V
V = l × b × h
[tex]V=4 feet\times 4 feet \times 2.5 feet= 40 feet^3[/tex]
a) [tex]1 feet^3=7.48052 gallons[/tex]
[tex]V=40 feet^3=40\times 7.48052 gallons=299.221 gallons[/tex]
b) Density of water at 4°C = 1 kg /L
1 metric tonne of water = 264.17 gallons of water
[tex]V=299.221 gallons=\frac{299.221}{264.17}[/tex] metric tonne of water
[tex]V=1.1327[/tex] metric tonne of water
Plants breathe in carbon dioxide to make sugar through photosynthesis. How much sugar can they create if 200 grams of carbon dioxide are used? 6 CO2 + 6 H2O -> C6H12O6 + 6 O2 A. 136.48 grams B. 180.16 grams C. 30.03 grams D. 0.76 grams
Answer: The correct answer is Option A.
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 carbon dioxide:Given mass of carbon dioxide = 200 g
Molar mass of carbon dioxide = 44 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of carbon dioxide}=\frac{200g}{44g/mol}=4.54mol[/tex]
The given chemical equation of photosynthesis reaction follows:
[tex]6CO_2+6H_2O\rightarrow C_6H_{12}O_6+6O_2[/tex]
By Stoichiometry of the reaction:
If 6 moles of carbon dioxide produces 1 mole of glucose.
Then, 4.54 moles of carbon dioxide will produce = [tex]\frac{1}{6}\times 4.54=0.756mol[/tex]
Now, calculating the mass of glucose from equation 1, we get:
Molar mass of glucose = 180.2 g/mol
Moles of glucose = 0.756 moles
Putting values in equation 1, we get:
[tex]0.756mol=\frac{\text{Mass of glucose}}{180.2g/mol}\\\\\text{Mass of glucose}=136.48g[/tex]
Hence, the correct answer is Option A.
Magnesium has 12 protons. What charge do you expect it to have when it ionizes? Why?
Answer: This element has +2 charge on it.
Explanation:
An ion is formed when an atom looses or gains electrons.
When an atom looses electrons, it leads to the formation of positive ion known as cation.When an atom gains electrons, it leads to the formation of negative ion known as anion.Magnesium is the 12th element of the periodic table having electronic configuration of [tex]1s^22s^22p^63s^2[/tex]
This element will loose 2 electrons to attain stable electronic configuration and leads to the formation of a cation having formula [tex]Mg^{2+}[/tex]
Hence, this element has +2 charge on it.
What are the three ways resources are classified?
Answer:
On the basis of ownership, distribution, durabilities.
Explanation:
In 1933, the concept of resources was given Zimmerman as a resource signifies possibility and may b a means to an end. According to him resources satisfy human wants and needs, having two important functions of utility and ability. Based on durability, they are either Fund or exhaustible resources. These get destroyed after use. Flow or inexhaustible resource remains unchanged even after continuous use like reiver, sea, and land. Based on ownership, they are International means used by the global population. National resource means used by one nation in one country. And individual searches money or property resources etc. And based on availability they are Ubiquitous and localized .like sunshine and the air is available everywhere.A chemist prepares a solution of zinc oxalate by measuring out of zinc oxalate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's zinc oxalate solution. Round your answer to significant digits. 0.0075 umol 450 mL
The concentration of a 0.0075 umol of zinc oxalate in a 450 mL solution is 1.67 x [tex]10^{-8[/tex] mol/L or 0.0000000167 M.
Explanation:To calculate the concentration of the zinc oxalate solution, we first convert the given quantity of zinc oxalate from umol to mol.
Converting 0.0075 umol to mol gives us 0.0075 x [tex]10^{-6[/tex] mol, which is 7.5 x [tex]10^{-9[/tex] mol.
Molarity is defined as the number of moles of solute per liter of solution.
So, we also need to convert 450 mL to liters, giving us 0.45L.
The concentration (C) is then calculated by dividing the number of moles (n) by the volume (V) in liters.
So, the molarity of the zinc oxalate solution can be calculated as follows: C = n/V = 7.5 x [tex]10^{-9[/tex] mol / 0.45L which equals 1.67 x [tex]10^{-8[/tex] mol/L, or 0.0000000167 M.
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Discuss the advantages of using building information modeling (BIM).
Answer:
The advantage of using building information modeling (BIM) are as follows:
1.Model based cost estimation
2. Preconstruction project visualization
3.Safe construction site
4. Improve scheduling
5.Improve coordination and clash detection
6.Reduced mitigated risk and cost
7.Improve prefabrication
8.Better collaboration and communication
9. Strong facility management
10.Improve sequencing
Five different substances are given to you to be dissolved in water. Which substances are most likely to undergo dissolution in water? Check all that apply. View Available Hint(s) Check all that apply. lithium iodide, LiI heptane, C7H16 octane, C8H18 sodium fluoride, NaF potassium iodide, KI
Answer:
Lithium iodide, sodium fluoride and potassium iodide are more likely to undergo dissolution in water.
Explanation:
Water is a polar substance, which means that it will be a good solvent for other polar substances and salts.
LiI, NaF and KI are all salts that easily dissociate in water to produce ions. The ions will be surrounded by water molecules (solvatation) due to electrostatic interactions.
Heptane and octane are both non-polar substances that have no significant charges to interact with water molecules. Therefore, this substances will not dissolve in water.
Final answer:
Lithium iodide, sodium fluoride, and potassium iodide are ionic compounds that are most likely to dissolve in water, a polar solvent. Nonpolar substances like heptane and octane are less likely to dissolve in water.
Explanation:
When considering the solubility of substances in water, we must account for the polarity of both the solute and the solvent. Water is a polar solvent, which means it can easily dissolve other polar compounds and ionic compounds due to its ability to form ion-dipole interactions. Considering the substances provided, lithium iodide (LiI), sodium fluoride (NaF), and potassium iodide (KI) are ionic compounds and are most likely to undergo dissolution in water.
On the other hand, heptane ([tex]C_{7} H_{16}[/tex]) and octane ([tex]C_{8} H_{18}[/tex]) are hydrocarbons, which are nonpolar substances. Nonpolar substances do not dissolve well in polar solvents like water, thus making these substances less likely to dissolve in water. Instead, they would be more soluble in nonpolar solvents such as hexane or other hydrocarbons.
The peregrine falcon has been measured as Traveling up to 350 km/hr in a dive. if this falcon can fly to the moon at this speed, how many seconds would it take?
Answer:
4 × 10⁶ sec
Explanation:
The distance between the earth and the moon = 384,400 km
The speed of the peregrine falcon = 350 km/hr
Considering,
Distance = Speed × Time
So,
Time = Distance / Speed = 384,400 km / 350 km/hr = 1098.28571 hrs
Also,
1 hr = 3600 sec
So,
1098.28571 hrs = 3600 × 1098.28571 s ≅ 4 × 10⁶ sec
Thus time taken by peregrine falcon if falcon fly to the moon = 4 × 10⁶ sec
It would take the peregrine falcon approximately 3,953,044 seconds to fly to the moon at a speed of 350 km/hr.
Explanation:If the peregrine falcon can travel up to 350 km/hr in a dive, let's calculate how long it would take for the falcon to fly to the moon at this speed. The average distance from Earth to the moon is approximately 384,400 km.
To find the time it would take, we can use the formula:
Time = Distance/Speed
So, Time = 384,400 km / 350 km/hr = 1098.29 hours.
Converting hours to seconds, we have:
Time = 1098.29 hours x 60 minutes x 60 seconds = 3,953,044 seconds.
Therefore, it would take the peregrine falcon approximately 3,953,044 seconds to fly to the moon at a speed of 350 km/hr.
caculate the kinetic energy in J of an electron moving at
6.00x 10 to the sixth power m/s.
Answer:
[tex]1.64x10^-^1^7 J[/tex]
Explanation:
Due to you know the velocity of the electron, the only thing that you need to do is used the Newtonian kinetic energy formula. The kinetic energy is defined as the work needed by motion body of a given mass to accelerate from rest to its know velocity:
[tex]KE=1/2mv^2=[kg*(m/s)^2]=[J][/tex]
[tex]m_e_- =9.1093835x10^-^3^1 kg [/tex]
[tex]KE=9.11x10^-^3^1 kg*(6.00x10^6 m/s)^2=1.64x10^-^1^7 J[/tex]
4.00 grams of an unknown monoprotic acid is titrated with 0.75 M NaOH. It takes 88.81 mL of NaOH to completely neutralize the acid. What is the molecular weight of the acid?
Answer:
The molecular weight of the acid is 60.05 g/mol
Explanation:
Let's state the balanced chemical equation to represent the neutralization reaction:
NaOH + HAc → NaAc + H2O
where HAc is the representation of the monoprotic acid. As we can see, the relationship between the base and the acid is 1:1, that is 1 mole of NaOH reacts with 1 mole of the monoprotic acid HAc. So, let's calculate the moles of NaOH that where present in the 88.81 mL aliquot used to neutralize the acid:
1000 mL ---- 0.75 moles of NaOH
88.81 mL --- x = (88.81 mL × 0.75 moles)/1000 mL = 0.0666075 moles NaOH
As we stated before, 1 mole of NaOH will react with 1 mole of HAc, so 0.0666075 moles of NaOH will reacted with 0.0666075 moles of the acid. Having said that, because we already know the mass of the acid, we are able to determine the molecular weight of it:
0.0666075 moles of HAc ---- 4.00 g
1 mole of HAc ---- x = (1 mole × 4.00 g)/0.0666075 moles = 60.05 g/mole
A
pure solvent freezes at 12.0 C. A solution of 0.980 g of the solute
and 13.870 g of solvent froze at 5.1 C. The molar mass of the
solute is 178.2 g/mol. Calculate the freezing point depression
constant, Kf for the solvent.
Answer:
[tex]K_{f}[/tex] for solvent is [tex]17^{0}\textrm{C}.kg.mol^{-1}[/tex]
Explanation:
Let's assume that the solute is non-volatile as well as non-electrolyte.For a solution with non-volatile solute and non-electrolyte solute-[tex]\Delta T_{f}=K_{f}.m[/tex], where [tex]\Delta T_{f}[/tex] is depression in freezing point and m is molality of solution
Molality of solution (m) = (moles of solute/mass of solvent in kg)
= [tex]\frac{\frac{0.980}{178.2}}{0.01387}mol/kg[/tex]
= 0.396 mol/kg
[tex]\Delta T_{f}=(12.0-5.1)^{0}\textrm{C}=6.9^{0}\textrm{C}[/tex]
So, [tex]K_{f}=\frac{\Delta T_{f}}{m}=\frac{6.9}{0.396}^{0}\textrm{C}.kg.mol^{-1}=17^{0}\textrm{C}.kg.mol^{-1}[/tex]
What volume of sample, in mL, would be needed to make 2 mL of a 5-fold dilution? (3 significant figures needed)
Answer:
0.400 mL
Explanation:
Hello, the dilution factor (in folds) is given by:
[tex]folds=\frac{total_{volume}}{sample_{volume}}[/tex]
Thus, the sample volume with three significant figures is given by:
[tex]sample_{volume}=\frac{2mL}{5"folds"}=0.400 mL[/tex]
Best regards.
Investigators decide to analyze the purity of a preparation of antibody molecules using SDS polyacrylamide-gel electrophoresis (SDS-PAGE). On Lane 1 of the gel, they load a sample of the antibody. On Lane 2, they load an antibody sample that has been treated with a reducing agent called mercaptoethanol, which breaks disulfide linkages. Following electrophoresis, they see distinct bands representing polypeptides with molecular weights of 50 kD and 25 kD in Lane 2 and only one band weighing 150 kD in Lane 1. What can the investigators conclude about their antibody based on the results of this experiment
Answer:
Their antibody is composed by subunits that have molecular weights of 50 kD and 25 kD, and each of these subunits has one Cys residue at least.
Explanation:
Their antibody is composed by subunits that are conected by an S-S bond that takes place in their Cys residue. When the antibody is treated with a reducing agent, these S-S bond are reduced to S-H, thus the subunits are no longer connected to each other.
The original antibody weights 150 kD, as seen in Lane 1. And the combination of these subunits are seen in Lane 2: this means there is not only one subunit of 50 kD and one of 25 kD. Rather, these subunits are repeated in the antibody, in a way such that their combined weight add ups to 150 kD (for instance 2 subunits of 50 kD and 2 subunits of 25 kD).
Final answer:
Based on SDS-PAGE analysis, investigators can conclude that the antibody under study is a multimeric protein made of polypeptide chains with molecular weights of 50 kD and 25 kD, held together by disulfide bonds that were reduced by mercaptoethanol.
Explanation:
Investigators utilized SDS-PAGE to analyze the purity of an antibody preparation. Upon electrophoresis, Lane 1, which contained untreated antibody sample, showed a single band at 150 kD. However, Lane 2, with antibody treated with mercaptoethanol, exhibited two distinct bands at molecular weights of 50 kD and 25 kD. The presence of these two bands in Lane 2, which was absent in Lane 1, indicates that the antibody molecule was originally composed of multiple polypeptide chains held together by disulfide bonds. Mercaptoethanol reduced these disulfide bonds, allowing the constituent polypeptide chains to be separated under electrophoretic conditions and revealing the true subunit composition of the antibody. Therefore, the investigators can conclude that the antibody is a multimeric protein, likely composed of two 50 kD chains and at least one 25 kD chain that were originally connected by disulfide bonds.
Calculate ΔS°for the combustion of ammonia.
4NH3(g) + 3O2(g) → 2N2(g) + 6H2O(l)
Substance NH3(g) O2(g) N2(g) H2O(l)
S°(J/K·mol) 192 205.1 192 70
-135 J
-579 J
-387 J
579 J
Answer: The [tex]\Delta S^o[/tex] of the reaction is [tex]-579JK^{-1}[/tex]
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.
The equation representing entropy change of the reaction follows:
[tex]\Delta S_{rxn}=\sum [n\times \Delta S^o_{products}]-\sum [n\times \Delta S^o_{reactants}][/tex]
For the given chemical equation:
[tex]4NH_3(g)+3O_2(g)\rightarrow 2N_2(g)+6H_2O(l)[/tex]
We are given:
[tex]\Delta S^o_{NH_3}=192Jmol^{-1}K^{-1}\\\Delta S^o_{O_2}=205.1Jmol^{-1}K^{-1}\\\Delta S^o_{N_2}=192Jmol^{-1}K^{-1}\\\Delta S^o_{H_2O}=70Jmol^{-1}K^{-1}[/tex]
Putting values in above equation, we get:
[tex]\Delta S^o_{rxn}=[(6\times \Delta S^o_{H_2O})+(2\times \Delta S^o_{N_2})]-[(4\times \Delta S^o_{NH_3})+(3\times \Delta S^o_{O_2})][/tex]
[tex]\Delta S^o_{rxn}=[(6\times 70)+(2\times 192)]-[(4\times 192)+(3\times 205.1)]=-579JK^{-1}[/tex]
Hence, the [tex]\Delta S^o[/tex] of the reaction is [tex]-579JK^{-1}[/tex]
What is the pH of a solution that is 0.10 M formic acid and 0.0065 M formate (the conjugate base)? Ka of formic acid = 1.77 x 10-4
Answer:
pH = 2.56
Explanation:
The Henderson-Hasselbalch equation relates the pH to the Ka and ratio of the conjugate acid-base pair as follows:
pH = pKa + log([A⁻]/[HA]) = -log(Ka) + log([A⁻]/[HA])
Substituting in the value gives:
pH = -log(1.77 x 10⁻⁴) + log((0.0065M) / (0.10M))
pH = 2.56
The pH of a 0.10 M formic acid and 0.0065 M formate solution can be calculated using the Henderson-Hasselbalch equation and a given Ka for formic acid of 1.77 x 10-4. The resulting pH is approximately 3.04.
Explanation:In order to find the pH of a solution consisting of a weak acid (formic acid, HCOOH) and its conjugate base (formate, HCOO-), you'd use the Henderson-Hasselbalch equation, which is pH = pKa + log([A-]/[HA]), where [A-] is the molarity of the conjugate base (here, formate, 0.0065 M) and [HA] is the molarity of the weak acid (here, formic acid, 0.10 M). The pKa is found by taking the negative logarithm of the Ka value, so pKa = -log(Ka) = -log(1.77 x 10-4) = 3.75.
Using these values in the Henderson-Hasselbalch equation: pH = 3.75 + log(0.0065/0.10) this results in a pH of approximately 3.04
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Write a chemical equation for the dissolution of the AgCl precipitate upon the addition of NH,(aq).
Explanation:
White precipitate of silver chloride get dissolves in excess ammonia to formation of complex between silver ions, chloride ions and ammonia molecules.
The chemical reaction is given as:
[tex]AgCl(s)+2NH_3(aq)\rightarrow Ag[(NH_3)_2]^+Cl^-(aq)[/tex]
When 1 mole of silver chloride is added to 2 mole of an aqueous ammonia it form coordination complex of diaaminesilver(I) chloride.
Final answer:
The chemical equation for the dissolution of AgCl precipitate with the addition of ammonia is [tex]AgCl(s) + 2NH_3(aq) < = > Ag(NH_3)_2+(aq) + Cl-(aq).[/tex] Ammonia interacts with [tex]Ag^+[/tex] to form a complex ion, increasing the solubility of AgCl significantly.
Explanation:
The dissolution of AgCl precipitate upon the addition of NH3(aq) is described by the following chemical equation:
[tex]AgCl(s) + 2NH_3(aq) \ < = > Ag(NH_3)_2+(aq) + Cl−(aq)[/tex]
When ammonia (NH3) is added to a solution containing AgCl, it reacts with the [tex]Ag^+[/tex] ions to form the complex ion [tex]Ag(NH_3)_2^+[/tex]. This acts to decrease the concentration of [tex]Ag^+[/tex] ions in solution. According to Le Chatelier's principle, the solubility of AgCl will increase to re-establish equilibrium, which leads to the dissolution of the AgCl precipitate.
The net effect of adding ammonia is a significant increase in the solubility of AgCl, as indicated by a change in the equilibrium constant from 1.8 x [tex]10^-10[/tex] in pure water to 3.0 x [tex]10^3[/tex] in the presence of dissolved ammonia.
A woolly rhinocerous skeleton (Coelodonta antiquitatis) found in Poland contains 1.30% of the C-14 found in living animals. How long ago did the organism die?
Answer:
The organism died 35900 years ago
Explanation:
Half life C-14 is 5730 years.For decay of radioactive nuclides: [tex]\frac{N}{N_{0}}=(\frac{1}{2})^{\frac{t}{t_{\frac{1}{2}}}}[/tex][tex]\frac{N}{N_{0}}[/tex] is the fraction of radioactive nuclide remain present after t time and [tex]t_{\frac{1}{2}}[/tex] is the half-life of radioactive nuclideHere [tex]\frac{N}{N_{0}}[/tex] is 0.013 and [tex]t_{\frac{1}{2}}[/tex] is 5730 yerasPlug-in all the values in the above equation:
[tex]0.013=(\frac{1}{2})^{\frac{t}{5730years}}[/tex]
So, t = 35900 years
Hence the organism died 35900 years ago
A 1004.0g sample of calcium carbonate that is 95.0% pure
gives225L of CO2 at STP when reacted with an excess
ofhydrochloric acid. What is the density (in g/L) of the
carbondioxide?
Answer:
The density of carbon dioxide is 1,86 g/L
Explanation:
The global reaction is:
2 HCl (aq)+ CaCO₃ (s) → CaCl₂(aq)+ H₂O(l)+ CO₂(g)
To obtain density it is necessary to obtain calcium carbonate moles -with molar mass of CaCo₃ = 100,09 g/mol- that are the same than CO₂ moles. Then, this moles must be converted to grams -CO₂ weights 44,01 g/mol- and, with the given liters (225 L) will be possible to know density, thus:
1004,0g × 95,0% = 953,8 g of CaCO₃
953,8 g of CaCO₃ ×[tex]\frac{1 mol}{100,09 g}[/tex] =
9,53 CaCO₃ moles ≡ CO₂ moles
9,53 CO₂ moles ×[tex]\frac{44,01 g}{1 mol}[/tex] = 419,4 g of CO₂
Thus, density of Carbon dioxide is:
[tex]\frac{419,4 g}{225 L}[/tex] = 1,86 g/L
I hope it helps!
Final answer:
To find the density of carbon dioxide, first calculate the mass of calcium carbonate used. Next, use the molar mass of CaCO3 to calculate the number of moles. Finally, calculate the density of CO2 using the mass and volume.
Explanation:
To find the density of carbon dioxide, we need to calculate the mass of carbon dioxide produced. From the given information, we know that a 1004.0g sample of calcium carbonate that is 95.0% pure gives 2.25L of CO2 at STP when reacted with an excess of hydrochloric acid. First, we calculate the mass of calcium carbonate used:
Mass of CaCO3 = 1004.0g * 0.95 = 954.8g
Next, we use the molar mass of CaCO3 (100.09 g/mol) to calculate the number of moles:
Moles of CaCO3 = 954.8g / 100.09 g/mol = 9.537 mol
According to the balanced chemical equation:
CaCO3 + 2HCl -> CaCl2 + CO2 + H2O
1 mole of CaCO3 produces 1 mole of CO2. Therefore, the number of moles of CO2 produced is also 9.537 mol.
Finally, we can calculate the density of CO2:
Density = Mass / Volume
Density = 9.537 mol * 44.01 g/mol / 2.25 L = 188.70 g/L
Drag the following in order, starting with the largest particle (can be seen) on the top and ending with the smallest particle (cannot be seen) on the bottom.
atoms
four carbon atoms
nucleus of an atom
electron
Answer:
Explanation:
four carbon atoms ------ atoms ------------nucleus of an atom------------electron
Atoms are the smallest indivisible particle in any substances. But atoms are also made up of other tiny particles which are subatomic in sizes. These particles are protons, neutrons and electrons.
Protons and neutrons are called the nucleons of an atoms. They are massive particles found in the nucleus of an atom. The nucleus is a very small area but very dense.
Electrons are negatively charged subatomic particles. The bulk of the volume of the atom is occupied by electrons orbiting the nucleus.
Together, the electrons and the nucleons makes up the subatomic particles in an atom.
A chemistry student needs 50.0 g of methyl acetate for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the student discovers that the density of methyl acetate is 0.934 g.cm . Calculate the volume of methyl acetate the student should pour out. Round your answer to 3 significant digits. x s ?
To obtain 50.0 g of methyl acetate, the student should measure out 53.5 cm³, using the density of methyl acetate which is 0.934 g/cm³.
Explanation:To calculate the volume of methyl acetate the student should pour out using its density, the formula density = mass/volume can be rearranged to volume = mass/density. Given that the density of methyl acetate is 0.934 g/cm³, and the student needs 50.0 g of methyl acetate, the volume can be calculated as follows:
volume = mass/density
volume = 50.0 g / 0.934 g/cm³
volume = 53.533 g/cm³
The student should measure out 53.5 cm³ of methyl acetate to obtain 50.0 g, rounding to 3 significant digits.
2 of 20 Which intermolecular force or bond is primarily responsible for the solubility of CH3OH in water? lonic bonding Hydrogen bonding Covalent bonding Dipole-dipole force lon-dipole force Navigator F10 F11 F12 PSC
Answer:
Hydrogen bonding
Explanation:
As a rule of thumb, "likes dissolve like", meaning polar solutes dissolve in polar solvents and nonpolar solutes in nonpolar solvents. In this case, water is polar (dipolar moment = 1.85 Debye) dissolves methanol which is also polar (dipolar moment = 1.69 Debye). Besides being dipoles, both molecules have atoms of Hydrogen with a covalent bond to more electronegative atoms of Oxygen. When this happens, stronger dipole-dipole interactions appear known as Hydrogen bonding. There is an electrostatic attraction between H (positive charge density) and O (negative charge density).
What information is provided by showing a molecule's stereochemistry?
Answer:
3-D shape of molecule and adjacent carbon atoms and their orientation.
Explanation:
Stereochemistry involves study of relative spatial positioning or arrangement of atoms which form structure of the molecules.
Stereochemistry studies focuses on the stereoisomers, which are the species which have same molecular formula but the sequence of the bonded atoms is different in the 3-D space of the atoms.
Thus,
Molecule's stereochemistry tells the 3-D shape of molecule and adjacent carbon atoms and their orientation.
Stereochemistry provides information about the three-dimensional structure of a molecule, including the arrangement of atoms and their spatial orientation.
Explanation:Stereochemistry is the study of the relative arrangement of atoms in molecules and their manipulation. It provides information about the three-dimensional structure of a molecule, including the arrangement of atoms and the spatial orientation of these atoms. By showing a molecule's stereochemistry, we can understand its shape, bonding patterns, and how it interacts with other molecules.
A molecule's stereochemistry can be represented using various models, such as ball-and-stick models, wedge-and-dash representations, or space-filling models. These models help visualize the three-dimensional structure of a molecule and show the arrangement of atoms in space.
The vapor pressure of substance X is 100. mm Hg at 1080.°C. The vapor pressure of substance X increases to 600. mm Hg at 1220.°C. Determine the molar heat of vaporization of substance X using the derived form of the Clausius-Clapeyron equation given below. (Include the sign of the value in your answer.) ____ kJ/mol
The molar heat of vaporization of substance X can be determined using the Clausius-Clapeyron equation. The molar heat of vaporization of substance X is -61.78 kJ/mol.
Explanation:The molar heat of vaporization of substance X can be determined using the Clausius-Clapeyron equation. The equation is given by:
ln(P₂/P₁) = -(ΔHvap/R)((1/T₂) - (1/T₁))
We can solve for ΔHvap by substituting the values given: P₁ = 100 mm Hg, T₁ = 1080 °C (or 1353 K), P₂ = 600 mm Hg, and T₂ = 1220 °C (or 1493 K).
ln(600/100) = -(ΔHvap/8.314)((1/1493) - (1/1353))
Solving for ΔHvap gives us a value of -61.78 kJ/mol. Therefore, the molar heat of vaporization of substance X is -61.78 kJ/mol.
In a gas grill, 29 lbs propane C3H8 are
burned with just enough air for complete combustion at a party. How
many lbs of combustion products are formed? Round your answer to
the nearest whole number.
Answer : The mass of combustion products formed are 134 lbs.
Explanation :
The balanced chemical reaction will be:
[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]
Given :
Mass of [tex]C_3H_8[/tex] = 29 lbs = 13154.2 g
conversion used : 1 lbs = 453.592 g
Molar mass of [tex]C_3H_8[/tex] = 44 g/mole
First we have to calculate the moles of [tex]C_3H_8[/tex].
[tex]\text{ Moles of }C_3H_8=\frac{\text{ Mass of }C_3H_8}{\text{ Molar mass of }C_3H_8}=\frac{13154.2g}{44g/mole}=298.9moles[/tex]
Now we have to calculate the moles of [tex]CO_2[/tex] and [tex]H_2O[/tex].
From the balanced chemical reaction we conclude that,
As, 1 mole of [tex]C_3H_8[/tex] react to give 3 moles of [tex]CO_2[/tex]
So, 298.9 mole of [tex]C_3H_8[/tex] react to give [tex]298.9\times 3=896.7[/tex] moles of [tex]CO_2[/tex]
and,
As, 1 mole of [tex]C_3H_8[/tex] react to give 4 moles of [tex]H_2O[/tex]
So, 298.9 mole of [tex]C_3H_8[/tex] react to give [tex]298.9\times 4=1195.6[/tex] moles of [tex]H_2O[/tex]
Now we have to calculate the mass of [tex]CO_2[/tex] and [tex]H_2O[/tex].
Molar mass of [tex]CO_2[/tex] = 44 g/mole
Molar mass of [tex]H_2O[/tex] = 18 g/mole
[tex]\text{Mass of }CO_2=\text{Moles of }CO_2\times \text{Molar mass }CO_2[/tex]
[tex]\text{Mass of }CO_2=896.7mole\times 44g/mole=39454.8g=86.98lbs[/tex]
and,
[tex]\text{Mass of }H_2O=\text{Moles of }H_2O\times \text{Molar mass }H_2O[/tex]
[tex]\text{Mass of }H_2O=1195.6mole\times 18g/mole=21520.8g=47.44lbs[/tex]
The total mass of products = Mass of [tex]CO_2[/tex] + Mass of [tex]H_2O[/tex]
The total mass of products = 86.98 + 47.44 = 134.42 ≈ 134 lbs
Therefore, the mass of combustion products formed are 134 lbs.
Be sure to answer all parts. Determine the overall orders of the reactions to which the following rate laws apply: (a) rate = k[NO2]2 (b) rate = k zero order first order 1.5 order second order 2.5 order third order zero order first order 1.5 order second order 2.5 order third ord
Answer :
(a) The rate of reaction is, second order reaction.
(b) The rate of reaction is, zero order reaction.
Explanation :
Rate of reaction : It is defined as the rate of change in concentration of reactant or product with respect to time.
Order of reaction : It is defined as the sum of the exponents or powers to which the molar concentration in the rate law equation are raised to express the observed rate of reaction.
The order of reaction depends on the power of reactant concentration.
(a) The given rate expression is,
[tex]Rate=k[NO_2]^2[/tex]
From this expression we conclude that the power of concentration of reactant [tex]NO_2[/tex] is 2.
That means it is a second order reaction.
(b) The given rate expression is,
[tex]Rate=k[/tex]
From this expression we conclude that the rate of reaction is equal to rate constant.
That means it is a zero order reaction.
What is the kinetic energy acquired by the electron in hydrogen atom, if it absorbs a light radiation of energy 1.08x10^1-7 J (A) 2.18x10- (B) 7.84x10- (C) 8.62x10-13 (D) 5.34x10-5
The kinetic energy acquired by the electron in a hydrogen atom when it absorbs a light radiation can be calculated using E = hf, where E is the energy of the radiation and f is the frequency of the radiation.
Explanation:When an electron in a hydrogen atom absorbs a light radiation, it gains kinetic energy. To calculate the energy gained, we can use the equation E = hf, where E is the energy of the radiation, h is Planck's constant (6.626 x 10^-34 J·s), and f is the frequency of the radiation. In this case, the energy of the radiation is given as 1.08 x 10^-7 J.
Since the electron absorbs the radiation, we know that the energy gained will be equal to the energy of the radiation. Therefore, the kinetic energy acquired by the electron in the hydrogen atom is 1.08 x 10^-7 J.
Which response gives the products of hydrolysis
ofNH4Cl?
A. NH4+ + HCl
B. NH3 + OH- + HCl
C. NH3 + H+
D. NH4OH + HCl
E. No hydrolysis occurs.
Answer : The correct option is, (C) NH₃ + H⁺
Explanation:
Hydrolysis : It is defined as the chemical reaction in which the breakdown of compound takes place due to reaction with water.
As per question:
First ammonium chloride completely dissociates into ion.
[tex]NH_4Cl(aq)\rightarrow NH_4^+(aq)+Cl^-(aq)[/tex]
Now ammonium ion react with water to give ammonia and hydronium or hydrogen ion.
The balanced hydrolysis reaction will be:
[tex]NH_4^++H_2O\rightarrow NH_3+H_3O^+[/tex]
Hence, the correct option is, (C) NH₃ + H⁺
Final answer:
The correct response to the products of hydrolysis of NH4Cl is 'NH3 + H+', because, during hydrolysis, NH4Cl separates into NH4+ and Cl- ions, with NH4+ reacting with water to form ammonia (NH3) and hydronium ions (H3O+). So the correct option is C.
Explanation:
The question asks which response gives the products of hydrolysis of NH4Cl. During hydrolysis, water is involved in breaking down a compound. In the case of NH4Cl, when it is dissolved in water, it separates into NH4+ ions and Cl− ions. The Chloride ion (Cl−) does not hydrolyze as it's the conjugate base of a strong acid (HCl) and has no significant basicity. On the other hand, the Ammonium ion (NH4+) is the conjugate acid of a weak base (NH3), and it will hydrolyze in water. The NH4+ accepts a hydroxide ion (OH−) from water, forming NH3 and H3O+ (hydronium ion). Therefore, the hydrolysis of NH4Cl will result in ammonia (NH3) and hydronium ions (H3O+).
Option C is the correct response: NH3 + H+. When NH4Cl hydrolyzes, it forms ammonia (NH3) and hydronium ions (H3O+), not hydrochloric acid (HCl). The correct formula of the products reflects the ammonia and hydronium ions formed.