Answer:
Keq = [ (C₁₉ H₈ Br₄ O₅ S)²⁻ ] [ H⁺ ] / [ (C₁₉ H₈ Br₄ O₅ S) H⁻ ]Explanation:
The equilibrium expression for the general equilibrium represented by the equation:
AB ⇄ A ⁺ + B⁻,is:
Keq = [A⁺] [B⁻] / [AB]Then, following that sketch, you obtain:
Reaction:(C₁₉ H₈ Br₄ O₅ S) H⁻ ⇄ (C₁₉ H₈ Br₄ O₅ S)²⁻ + H⁺
Equilibrium expression:Keq = [ (C₁₉ H₈ Br₄ O₅ S)²⁻ ] [ H⁺ ] / [ (C₁₉ H₈ Br₄ O₅ S) H⁻ ]
The square brackets are used to mean molar concentration (molariy).
A flexible container at an initial volume of 8.15 L contains 9.51 mol of gas. More gas is then added to the container until it reaches a final volume of 17.9 L. Assuming the pressure and temperature of the gas remain constant, calculate the number of moles of gas added to the container.
Answer : The number of moles of gas added to the container will be, 20.89 mole
Explanation :
According to the Avogadro's law, the volume of gas is directly proportional to the number of moles of gas at same pressure and temperature. That means,
[tex]V\propto n[/tex]
or,
[tex]\frac{V_1}{V_2}=\frac{n_1}{n_2}[/tex]
where,
[tex]V_1[/tex] = initial volume of gas = 8.15 L
[tex]V_2[/tex] = final volume of gas = 17.9 L
[tex]n_1[/tex] = initial number of moles of gas = 9.51 mole
[tex]n_2[/tex] = final number of moles of gas = ?
Now we put all the given values in this formula, we get the final moles of gas.
[tex]\frac{8.15L}{17.9L}=\frac{9.51mole}{n_2}[/tex]
[tex]n_2=20.89mole[/tex]
Therefore, the number of moles of gas added to the container will be, 20.89 mole
Find the enthalpy of neutralization of HCl and NaOH. 87 cm3 of 1.6 mol dm-3 hydrochloric acid was neutralized by 87 cm3 of 1.6 mol dm-3 NaOH. The temperature rose from 298 K to 317.4 K. The specific heat capacity is the same as water, 4.18 J/K g.
The enthalpy of neutralization of HCl and NaOH is 8.18 kJ/mol.
Explanation:The enthalpy of neutralization is the heat released or absorbed when an acid and a base react to form one mole of water. In this case, the reaction is between hydrochloric acid (HCl) and sodium hydroxide (NaOH).
From the given information, 87 cm3 of 1.6 mol dm-3 HCl is neutralized by 87 cm3 of 1.6 mol dm-3 NaOH. The temperature rose from 298 K to 317.4 K.
To calculate the enthalpy change, we can use the formula:
Enthalpy change of neutralization = (mole of limiting reactant) x (heat evolved per mole of reaction)
From the balanced equation: HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l)
This means that 1 mole of HCl reacts with 1 mole of NaOH to produce 1 mole of water. So, the heat evolved per mole of reaction is equal to the enthalpy change of neutralization.
Now, let's calculate the mole of the limiting reactant:
Given volume of HCl = 87 cm3 = 87 x 10-3 dm3
Given molarity of HCl = 1.6 mol dm-3
Mole of HCl = volume x molarity = (87 x 10-3) x 1.6 = 0.1392 mol
Since the mole of HCl and NaOH are equal, the mole of the limiting reactant is 0.1392 mol.
To determine the heat evolved per reaction, we need to divide the heat evolved by the mole of reaction:
Given temperature change = 317.4 K - 298 K = 19.4 K
Given the specific heat capacity of water = 4.18 J/K g
Assuming the density of the solutions is the same as water, we can use the mass of the solutions:
Mass of solution = volume x density = 87 x 10-3 dm3 x 1 g/cm3 = 87 g
Now, we can calculate the heat evolved:
Heat evolved = mass x specific heat capacity x temperature change = 87 g x 4.18 J/K g x 19.4 K = 8,177.56 J/mol
Convert the heat evolved from Joules to kilojoules:
The heat evolved = 8,177.56 J/mol = 8.18 kJ/mol (rounded to 2 decimal places)
Therefore, the enthalpy of neutralization of HCl and NaOH is 8.18 kJ/mol.
Be sure to answer all parts. The percent by mass of bicarbonate (HCO3−) in a certain Alka-Seltzer product is 32.5 percent. Calculate the volume of CO2 generated (in mL) at 37°C and 1.00 atm if a person were to accidentally ingest a 3.79-g tablet without following instructions. (Hint: The reaction occurs between HCO3− and HCl acid in the stomach.)
Answer : The volume of [tex]CO_2[/tex] will be, 514.11 ml
Explanation :
The balanced chemical reaction will be,
[tex]HCO_3^-+HCl\rightarrow Cl^-+H_2O+CO_2[/tex]
First we have to calculate the mass of [tex]HCO_3^-[/tex] in tablet.
[tex]\text{Mass of }HCO_3^-\text{ in tablet}=32.5\% \times 3.79g=\frac{32.5}{100}\times 3.79g=1.23175g[/tex]
Now we have to calculate the moles of [tex]HCO_3^-[/tex].
Molar mass of [tex]HCO_3^-[/tex] = 1 + 12 + 3(16) = 61 g/mole
[tex]\text{Moles of }HCO_3^-=\frac{\text{Mass of }HCO_3^-}{\text{Molar mass of }HCO_3^-}=\frac{1.23175g}{61g/mole}=0.0202moles[/tex]
Now we have to calculate the moles of [tex]CO_2[/tex].
From the balanced chemical reaction, we conclude that
As, 1 mole of [tex]HCO_3^-[/tex] react to give 1 mole of [tex]CO_2[/tex]
So, 0.0202 mole of [tex]HCO_3^-[/tex] react to give 0.0202 mole of [tex]CO_2[/tex]
The moles of [tex]CO_2[/tex] = 0.0202 mole
Now we have to calculate the volume of [tex]CO_2[/tex] by using ideal gas equation.
[tex]PV=nRT[/tex]
where,
P = pressure of gas = 1.00 atm
V = volume of gas = ?
T = temperature of gas = [tex]37^oC=273+37=310K[/tex]
n = number of moles of gas = 0.0202 mole
R = gas constant = 0.0821 L.atm/mole.K
Now put all the given values in the ideal gas equation, we get :
[tex](1.00atm)\times V=0.0202 mole\times (0.0821L.atm/mole.K)\times (310K)[/tex]
[tex]V=0.51411L=514.11ml[/tex]
Therefore, the volume of [tex]CO_2[/tex] will be, 514.11 ml
Atoms- 1 2 3 4
Protons- 8 10 9 8
Neutrons- 10 9 9 11
Electrons- 8 10 9 8
Which two are isotopes of one another?
Answer:
The ones with 8 protons
Explanation:
Since there are two of them with 8 protons, we can assume they are the same element. The first 8 proton element has 10 neutrons while the second has 11. This makes them isotopes of one another
A chemical reaction has reached equilibrium when
Calculate the pH of 1.00 L of the buffer 0.95 M CH3COONa/0.92 M CH3COOH before and after the addition of the following species. (Assume there is no change in volume.) (a) pH of starting buffer: (b) pH after addition of 0.040 mol NaOH: (c) pH after further addition of 0.100 mol HCl:
Answer: (a) pH = 4.774, (b) pH = 4.811 and (c) pH = 4.681
Explanation: (a) pH of the buffer solution is calculated using Handerson equation:
[tex]pH=pKa+log(\frac{base}{acid})[/tex]
pKa for acetic acid is 4.76. concentration of base and acid are given as 0.95M and 0.92M. Let's plug in the values in the equation and calculate the pH of starting buffer.
[tex]pH=4.76+log(\frac{0.95}{0.92})[/tex]
pH = 4.76 + 0.014
pH = 4.774
(b) When 0.040 mol of NaOH (strong base) are added to the buffer then it reacts with 0.040 mol of acetic acid and form 0.040 mol of sodium acetate.
Original buffer volume is 1.00 L. So, the original moles of sodium acetate will be 0.95 and acetic acid will be 0.92.
moles of acetic acid after addition of NaOH = 0.92 - 0.040 = 0.88
moles of sodium acetate after addition of NaOH = 0.95 + 0.040 = 0.99
Let's again plug in the values in the Handerson equation:
[tex]pH=4.76+log(\frac{0.99}{0.88})[/tex]
pH = 4.76 + 0.051
pH = 4.811
(c) When 0.100 mol of HCl are added then it reacts with exactly 0.100 moles of sodium acetate(base) and form 0.100 moles of acetic acid(acid).
so, new moles of acetic acid = 0.92 + 0.100 = 1.02
new moles of sodium acetate = 0.95 - 0.100 = 0.85
Let's plug in the values in the equation:
[tex]pH=4.76+log(\frac{0.85}{1.02})[/tex]
pH = 4.76 - 0.079
pH = 4.681
The pH of the buffer can be calculated at each step using the Henderson-Hasselbalch equation, which requires the pKa of the acid and the ratio of the base to acid concentrations. When NaOH is added, it reacts with the acetic acid, changing this ratio and thus the pH. When HCl is added, it reacts with the acetate, again changing the ratio and pH.
Explanation:The initial pH of the buffer can be calculated using the Henderson-Hasselbalch equation. This equation requires the pKa, which for acetic acid is 4.74, and the ratio of the concentrations of the base (CH3COONa, or acetate) and acid (CH3COOH, or acetic acid). So we have pH = pKa + log([base]/[acid]) = 4.74 + log(0.95/0.92) ≈ 4.75. That's the starting pH of the buffer.
Now, when we add 0.040 mol NaOH, it will react with the acetic acid, converting it to acetate and thus increasing the [base]/[acid] ratio. The change in pH can again be calculated via the Henderson-Hasselbalch equation: pH = 4.74 + log((0.95 + 0.040)/(0.92 - 0.040)). Then, when we add 0.100 mol HCl, it will react with the acetate, converting it back to acetic acid and thus decreasing the [base]/[acid] ratio, again resulting in a pH shift that you can calculate the same way.
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How many liters of octane are in a shipping container that contains 45 moles?
A. 45 liters
B. 450 moles
C. 2 moles
D. 1,008 liters
Members of the order Testudines have an anapsid-like skull with one opening. However, molecular studies indicate that turtles descended from a diapsid ancestor. Why might this be the case?
Answer:
Explanation:because turtles will eventually get old and they will leave behind their family like the next generation
Using the Lewis Dot Structure, what does IF6+ look like?
I need this as soon as possible tytyy
Answer:
This ion is in an octahedral geometry.
See the diagram attached for the Lewis Dot Structure of the iodide hexafluoride cation [tex]\rm {IF_6}^{+}[/tex]. (Created with Google Drawings.)
Note that in this diagram,
A pair of double dots on an atom represent a lone pair of electrons.A single dash represents a single chemical bond.The square bracket and the superscript indicates that this structure is charged.Explanation:
The iodine in [tex]\rm {IF_6}^{+}[/tex] forms an expanded octet. There are twelve valence electrons in total around this atom.
Each of the six fluorine atom needs 8 - 7 = 1 electron to achieve an octet of eight electrons.The iodine atom needs 12 - 7 = 5 electrons to achieve an expanded octet of twelve electrons.The ion carries a positive charge of +1. Atoms in this ion lacks one extra electron.Overall, there needs to be [tex]6 \times 1 + 5 + 1= 12[/tex] more electrons for seven atoms to achieve an octet. They will form half that number of chemical bonds. That's [tex]12 / 2 = 6[/tex] bonds.
Now consider: what will be the geometry of this ion? There are six chemical bonds but no lone pair around the central iodine atom. The six [tex]\mathrm{I-F}[/tex] bonds repel each other equally. They will stay as far apart from each other as possible. As a result, the shape of the ion will be octahedral. Each of the fluorine atoms occupies a vertex.
One mole of hydrogen gas is reacted with oxygen gas to produce water in this reaction:
2 H2 + O2 → 2 H2O
In the lab you actually made 14 grams of water. What is the percent yield?
35.60%
100%
11.11%
77.60%
Answer:
77.6%
Explanation:
Parameters given:
Number of moles of H₂ = 1 mole
Actual yield = 14g
Equation of the reaction:
2H₂ + O₂ → 2H₂O
Solution
From the statement of the problem, we have been given the actual yield that was obtained during the laboratory procedure. Now, we find the theoretical yield and this would lead us to the percentage yield.
Percentage yield = [tex]\frac{actual yield}{Theoretical yield}[/tex] x 100
Theoretical yield:
From the stoichiometeric equation:
2moles of H₂ produced 2 moles of water
Hydrogen gas the limiting reactant and it is in short supply,
Therefore, 1 mole of water would be produced by 1 mole of hydrogen gas.
We use this to estimate the mass of the water that would be produced:
mass of water = number of moles of water x molar mass of water
Molar mass of H₂O = (2x1) + 16 = 18gmol⁻¹
mass of water = 1 mol x 18gmol⁻¹ = 18g
This is the theoretical yield
Percentage yield = [tex]\frac{actual yield}{Theoretical yield}[/tex] x 100
Percentage yield = [tex]\frac{14}{18}[/tex] x 100 = 77.6%
How long does helium last in latex balloons
Answer:
it will last I'll say about 12-19 or 20 hours
Explanation:
my explanation is it all depends on the time and the degrees because it can last for weeks (5-7) but it won't
float
hope that helps
Helium typically lasts about 12 to 24 hours in a latex balloon. This is due to helium's high effusion rate, meaning it escapes quickly through small pores in the latex material.
Explanation:In a latex balloon, helium typically lasts about 12 to 24 hours. This is mainly due to the effusion rate of helium, which is quite high because helium is a very light gas. A gas's effusion rate relates to how quickly it escapes through small pores or openings.
The balloon material, which in this case is latex, can only contain the gas for so long before it starts to leak out. As shown in the given photographs, a helium-filled balloon noticeably deflated after just 12 hours, whereas the argon-filled balloon remained inflated due to argon's lower effusion rate.
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How does an enzyme increase the rate of the chemical reaction it catalyzes?
Answer:
lowers activation energy
Answer:
Explanation:
An enzyme reduces the free energy of activation (EA) of the reaction it catalyzes.
Which is usually the slowest way to regulate a reaction in a metabolic pathway?
A) Covalent modification
B) Changing the enzyme concentration
C) Allosteric modulation
All of the above are usually equally as fast.
Answer:
B) Changing the enzyme concentration
The slowest way to regulate a reaction in a metabolic pathway is by changing the enzyme concentration.
Metabolic Pathway:It is series of chemical reactions that occurred in the cell. Metabolites referred to as species participating in an enzymatic reaction.
Role of Enzymes:
Enzymes act as catalysts – they allow a reaction to proceed more rapidly – and they also allow the regulation of the rate of a metabolic reaction
The binding of an enzyme to its substrate lowers the activation energy of the reaction. If an enzyme is present, the amount of energy needed to make a product is lowered.
In metabolic reactions there is transfer of electrons from one compound to another by processes catalyzed by enzymes.
Enzymes participates in increasing and decreasing the metabolism process inside our body. On increasing the substrate concentration, the rate of enzyme activity also increases.
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A student is investigating the affect of different salts on melting points. Four patches of ice of equal size are roped off and a different type of salt is poured on each, one receives table salt (NaCl), one receives Calcium Chloride (CaCl2), one receives Potassium Carbonate (KCO3) and the fourth receives inert sand instead. Each patch receives an equal amount of salt or sand. The student measures the volume of ice remaining and subtracts it from the original volume of ice to see how much melted away. What is a control variable in this experiment?
Answer:
The inert sand
Explanation:
A control variable is the variable in which the experiment does not depend on. The outcome of the control variable does not in any way validate or invalidate an experimental procedure.
The student seeks to investigate the effect of different salts on melting point. He used NaCl, CaCl₂, K₂CO₃ and inert sand. The first three are salts. Sand is made up of silica, SiO₂ and it is not a salt. Therefore, the control variable here is the inert sand. Sand is highly unreactive and would not in any significant way help the investigation.
Answer: Fourth one which received inert sand.
Explanation:
A control variable is the one which remains unchanged in an experiment. It does not receive any treatment. It is considered as a benchmark or standard for comparison of changes occurring in the dependent or experimental variable.
According to the given situation, the fourth one is the correct option as the inert sand will not have any effect over the melting of ice. This can be useful for comparison of the effect of salts on the ice.
Approximately when did the first plants and arthropods appear on land? A. 444 Ma B. 488 Ma C. 299 Ma D. 416 Ma
Answer:
A.
Explanation:
444 Ma
Answer:
444 ma is right
Explanation:
Which of the following accurately characterizes the process of freezing?
Because energy is released, freezing is an exothermic process.
Because energy is absorbed, freezing is an exothermic process.
Because energy is released, freezing is an endothermic process.
Because energy is absorbed, freezing is an endothermic process.
Answer:
because energy is released
Explanation:
freesing is an exothermic process
C. Because energy is released, freezing is an endothermic process.
what is the endothermic process?In thermochemistry, an endothermic system is any process with an increase in the enthalpy H of the system. In such a process, a closed system usually absorbs thermal energy from its surroundings, which is heat transferred into the system.
Endothermic reactions are chemical reactions wherein the reactants absorb heat energy from the surroundings to form products. these reactions lower the temperature in their surrounding region, thereby creating a cooling effect.
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Which substance would be found in higher concentration if the membrane were damaged? View Available Hint(s) Which substance would be found in higher concentration if the membrane were damaged? protein chloride creatinine glucose
Answer: the correct answer is protein
Explanation:
Large proteins are not normally filtered by a healthy glomerural membrane.
Hydrates that have a low vapor pressure and remove moisture from air are said to be ___. Question 8 options: effloresce hygroscopic solvation anhydrous
Answer:
Hygroscopic
Explanation:
An hygroscopic substance is one that absorbs moisture from the atmosphere and becomes wet. Their ability to remove water from air is less than that of deliquescent substances. Most of the solid hygroscopic substances forms pasty substances and not solutions like the deliquescent compounds.
Examples are sodium trioxonitrate(v), copper(ii) oxide e.t.c
Efflorescence compounds gives off their water of crystallization to the atmosphere.
Hydrates capable of removing moisture from the air due to their low vapor pressure are known as hygroscopic.
Hydrates that have a low vapor pressure and can remove moisture from air are hygroscopic. Substances such as anhydrous calcium chloride and magnesium chloride exhibit hygroscopic properties due to their ability to absorb moisture, ultimately becoming hydrates in the process.
For example, anhydrous calcium chloride mixed with cobalt chloride serves as both a drying agent and an indicator; cobalt chloride is blue when anhydrous and pink when hydrated, thus revealing the condition of the desiccant.
Furthermore, the presence of nonvolatile solutes, such as these hydrates, can lower the vapor pressure of a solution by preventing the evaporation of solvent molecules. The waters of hydration in compounds are loosely bound water molecules that can often be removed through heating, turning hydrates back into their anhydrous form.
A sample of an unknown compound is vaporized at 180.°C. The gas produced has a volume of 2010.mL at a pressure of 1.00atm, and it weighs 2.73g. Assuming the gas behaves as an ideal gas under these conditions, calculate the molar mass of the compound. Round your answer to 3 significant digits.
The molar mass of the unknown compound under the given conditions, deemed to behave as an ideal gas, is approximately 176.124 g/mol. We determined this via the ideal gas law, which allowed us to find the number of moles, and subsequently the molar mass through division of the compound's mass by the number of moles.
Explanation:The problem involves calculating the molar mass of an unknown compound acting as an ideal gas under specific conditions. We begin by using the ideal gas law (PV = nRT), but we rearrange it to find the number of moles (n = PV/RT). Given the pressure (P = 1.00 atm), volume (V = 2010 mL or 2.01 L), and temperature in degrees Celsius (which must be converted to Kelvins, T = 180 + 273 = 453 K), and knowing the gas constant (R = 0.0821 L.atm/mol.K), we can calculate n.
Once we have the number of moles, we can find the molar mass by dividing the mass of the compound (given as 2.73g) by the number of moles. Thus, the molar mass of the compound is found to be approximately 176.124 g/mol.
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An _____ reaction results when the energy released by the formation of products is greater than the energy required to break the bonds in the reactants.
Answer:
Exothermic
Explanation:
An exothermic reaction results when the energy released by the formation of products is greater than the energy required to break the bonds in the reactants.
Which correctly lists the following in order of increasing entropy? i. 1 mol of HCl (g) at 50 ° C ii. 1 mol of NaCl (s) at 25 ° C iii. 2 mol of HCl (g) at 50 ° C iv. 1 mol of HCl (g) at 25 ° C
Answer:
The order of increasing entropy will be:
1 mol of NaCl (s) at 25 ° C < 1 mol of HCl (g) at 25 ° C< 1 mol of HCl (g) at 50 ° C < 2 mol of HCl (g) at 50 ° C
Explanation:
The entropy increases with
a) increase in temperature
b) state of matter (the entropy order of matter is gas > liquid > solid)
So here
i) 1 mol of HCl (g) at 50 ° C : it is gas at high temperature as compared to HCl gas at lower temperature.
ii. 1 mol of NaCl (s) at 25 ° C : this is solid so will have lower entropy than gas.
iii. 2 mol of HCl (g) at 50 ° C: the moles are more so will have more entropy than 1 mol of HCl (g) at 50 ° C
iv. 1 mol of HCl (g) at 25 ° C : will have lower entropy than HCl gas at higher temperature but will have higher entropy than solid NaCl.
The correct order of increasing entropy is given as:
1 mol of NaCl (s) at 25 ° C < mol of HCl (g) at 50 ° C < 1 mol of HCl (g) at 25 ° C < 2 mol of HCl (g) at 50 ° C
What is entropy?Entropy can be defined as that measure of thermal energy of a system per unit temperature that is unavailable for doing work.
Mathematically, the entropy change in a chemical reaction is given by:
The sum of the entropies of the products - the sum of the entropies of the reactants.
In conclusion, the correct order of increasing entropy is given as
1 mol of NaCl (s) at 25 ° C < mol of HCl (g) at 50 ° C < 1 mol of HCl (g) at 25 ° C < 2 mol of HCl (g) at 50 ° C
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What process occurs when heavier chemicals fall to Earth as dry particles?
acid rain
condensation
deposition
Acid rain is the process that involves heavy chemicals falling to the Earth
as dry particles.
Acid rain is common in areas which have a lot of industries which release
chemicals into the atmosphere. With time, these chemicals accumulate and
falls to earth as dry particles through precipitation.
The acid rain normally contains water which pushes the chemicals down and the water is usually acidic with a pH between 4.2 and 4.4 as a result of the chemicals.
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In the equation for the formation of magnesium sulfide shown, which atom gains electrons?
Mg + S → MgS
S + 2e⁻ → S²⁻ (sulfur will gain electrons)
Mg - 2e⁻ → Mg²⁺ (magnesium will lose electrons)
Magnesium is a metal which tends to give electrons which are received by the sulfur, which is a nonmetal and tends to gain electrons.
Answer: The atom which gains electrons is sulfur
Explanation:
Oxidation reaction is defined as the chemical reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.
[tex]X\rightarrow X^{n+}+ne^-[/tex]
Reduction reaction is defined as the chemical reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.
[tex]X^{n+}+ne^-\rightarrow X[/tex]
For the given chemical equation:
[tex]Mg+S\rightarrow MgS[/tex]
Oxidation half reaction: [tex]Mg\rightarrow Mg^{2+}+2e^-[/tex]
Reduction half reaction: [tex]S+2e6-\rightarrow S^{2-}[/tex]
Hence, the atom which gains electrons is sulfur
Radioactive isotopes a. have an excess number of neutrons. b. behave the same chemically and physically but differ biologically from other isotopes. c. are electrically unbalanced. d. are the same physically and biologically but differ from other isotopes chemically.
Answer:
a. have an excess number of neutrons.
Explanation:
Every atomic nucleus have a specific neutron/proton ratio that makes them stable. Any nucleus with a neutron/proton ratio that differs from the stability ration will become unstable. An unstable nucleus will split up and emit small particles of matter and/electromagnetic ionizing radiation. This makes an atom radioactive.
Therefore, an atom with excess number of neutrons is a radioactive isotope.
The volume of a sample of hydrogen gas was decreased from 12.16 L to 5.45 L at constant temperature. If the final pressure exerted by the hydrogen gas sample was 5.09 atm, what pressure did the hydrogen gas exert before its volume was decreased?
Answer : The pressure of the hydrogen gas exert before its volume was decreased will be, 2.28 atm
Explanation :
According to the Boyle's law, the pressure of the gas is inversely proportional to the volume of the gas at constant temperature of the gas and the number of moles of gas.
[tex]P\propto \frac{1}{V}[/tex]
or,
[tex]PV=k[/tex]
or,
[tex]P_1V_1=P_2V_2[/tex]
where,
[tex]P_1[/tex] = initial pressure of the gas = ?
[tex]P_2[/tex] = final pressure of the gas = 5.09 atm
[tex]V_1[/tex] = initial volume of the gas = 12.16 L
[tex]V_2[/tex] = final volume of the gas = 5.45 L
Now put all the given values in this formula, we get the initial pressure of the gas.
[tex]P_1\times 12.16L=5.09atm\times 5.45L[/tex]
[tex]P_1=2.28atm[/tex]
Therefore, the pressure of the hydrogen gas exert before its volume was decreased will be, 2.28 atm
Calculate the heat of decomposition for this process at constant pressure and 25°C: CaCO3(s) → CaO(s) + CO2(g) The standard enthalpies of formation for the reactant are: ΔHf CaCO3(s) = −1206.9 kJ/mol ; ΔHf CaO(s) = −635.6 kJ/mol; ΔHf CO2(g) −393.5 kJ/mol
Answer:
177.8kJ/mol
Explanation:
In this reaction, the heat of decomposition is the same as the heat of formation. This is a decomposition reaction.
Given parameters:
ΔHf CaCO₃ = -1206.9kJ/mol
ΔHf CaO = −635.6 kJ/mol
ΔHf CO₂ = −393.5 kJ/mol
The heat of decomposition =
Sum of ΔHf of products - Sum of ΔHf of reactants
The equation of the reaction is shown below:
CaCO₃ → CaO + CO₂
The heat of decomposition = [ -635.6 + (-393.5)] - [−1206.9 ]
= -1029.1 + 1206.9
= 177.8kJ/mol
The heat of decomposition given by the difference in the ΔH of product and reactant is 177.8 kj/mol
Given the equation for the decomposition process :
CaCO3(s) → CaO(s) + CO2(g)The heat for the decomposition process is the difference of the sum of heat of the product and the heat of the reactant :
Reactant :
CaCO3(s) = - 1206.9 kj/molProduct :
CaO(s) + CO2(g) = - 635. 6 + (-393.5) = - 1029.1 kj/molHeat of decomposition :
ΔHproduct - ΔHreactantHeat of decomposition = - 1029.1 - (- 1206.9)
Heat of decomposition = -1029.1 + 1206.9 = 177.8 kj/mol
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Why might an idea or hypothesis be discarded? A. If another scientist doesn't like it. B. If evidence also supports another hypothesis. C. If it is tested and the evidence does not support it. D. If a politician disagrees with it.
Answer:
C. If it is tested and the evidence does not support it.
Explanation:
A hypothesis is more less a scientific guess. Before such a guess or prediction is made, empirical observations and deductions are first made. It is from the result of the observations that a hypothesis statement is made.
For a hypothesis to become widely adopted and accepted, it must be testable within the limits of the experiment as described by the proposer. When subjected to test and it agrees, the status of a hypothesis can be upgraded.
If the hypothesis is tested and evidence contrasts the result being sort for, a hypothesis will be discarded.
Methanol, CH3OH, has been considered as a possible fuel. Consider its oxidation: 2 CH3OH(l) + 3 O2(g) → 2 CO2(g) + 4 H2O(g) ΔG = -1372 kJ/mol. What is the maximum work that can be obtained by oxidizing 0.50 mol of methanol under standard conditions?
Final answer:
The maximum work obtainable from oxidizing 0.50 mol of methanol under standard conditions is -686 kJ. This calculation is done by multiplying the given Gibbs free energy (ΔG) for the reaction by the number of moles of methanol.
Explanation:
The student's question pertains to the calculation of the maximum work that can be obtained by oxidizing methanol under standard conditions, given the Gibbs free energy change (ΔG) of the reaction. To find this, you use the equation ΔG = -nFE, where 'n' is the number of moles of electrons transferred, 'F' is the Faraday constant (96,485 C/mol e-), and 'E' is the electromotive force (emf). However, since ΔG is already provided and is the amount of energy available to do work at constant temperature and pressure, the calculation in this case is simpler and does not require the use of Faraday constantor emf.
The reaction, as given, is 2 CH3OH(l) + 3 O2(g) → 2 CO2(g) + 4 H2O(g) with ΔG = -1372 kJ/mol for the oxidation of 1 mole of methanol.
To calculate the maximum work for 0.50 mol of methanol:
Multiply ΔG by the number of moles of methanol being oxidized (0.50 mol).
Work = -1372 kJ/mol * 0.50 mol = -686 kJ.
Therefore, the maximum work that can be obtained by oxidizing 0.50 mol of methanol under standard conditions is -686 kJ. The negative sign indicates that the reaction is exergonic, releasing energy that can be used to do work.
The boiling point of propanoic acid is higher than that of 1-butanol because: propanoic acid has a higher molecular weight than 1-butanol. propanoic acid is more soluble in water than 1-butanol. propanoic acid is a better hydrogen bond donor than 1-butanol. propanoic acid forms hydrogen bonded dimers and 1-butanol does not. 1-butanol forms hydrogen bonded dimers and propanoic acid does not.
Answer:
propanoic acid forms hydrogen bonded dimers and 1-butanol does not.
Explanation:
Propanoic acids will have a higher boiling point because it forms dimers.
The two compounds have hydrogen bonds as their predominant intermolecular bonds. The intermolecular determines a lot about the physical properties of a substance such as it's viscosity, boiling point, melting point etc.
The two compounds have hydrogen bonds which are bonds that occur between between hydrogen and a more electronegative atom. The electronegative atoms are usually oxygen,nitrogen and fluorine.
In a compound of 1-butanol, we have just a single hydrogen bond between the hydrogen on one compound and the oxygen on the hydroxyl group of another one.
For, propanoic acids, dimerization occurs. Here, we have two hydrogen bonds. The alkanoic acid functional group furnishes the bond. This bond forms between the carbonyl group and hydrogen on a compound and the hydroxyl group and another hydrogen on the same compound.
What is the concentration of hydronium ions in a 0.01m solution of hcl?
Answer:
0.01 MExplanation:
1) Dissociation:
Since HCl is a strong acid, it dissociates 100% in water to form hydronium (H₃O⁺) and chloride (Cl⁻) ions, as per this chemical equation:
HCl + H₂O → H₃O⁺ + Cl⁻2) Concentrations:
Hence, each mole of HCl molecules yields 1 mol of hydronium ( H₃O⁺) and 1 mol of chloride (Cl⁻) ions.
Thus, [HCl] = [H₃O⁺] = [Cl⁻] = 0.01 M
3) Conclusion: the concentraion of hydronium ions in a 0.01 M solution of HCl is 0.01 M