Question 1

Hydrochloric acid is prepared by bubbling hydrogen chloride gas through water. What is the concentration of a solution prepared by dissolving 225 L of HCl(g) at 37°C and 89.6 kPa in 5.25 L of water?

Accepted Answer

The answer of Hydrochloric acid is prepared by bubbling hydrogen...

Question 2

Assuming ideal behavior, what is the density of argon gas at STP, in g/L?

Accepted Answer

The answer of Assuming ideal behavior, what is the density...

Question 3

Ima Chemist found the density of Freon-11 (CFCl₃) to be 5.58 g/L under her experimental conditions. Her measurements showed that the density of an unknown gas was 4.38 g/L under the same conditions. What is the molar mass of the unknown?

Accepted Answer

The answer of Ima Chemist found the density of Freon-11...

Question 4

What is the pressure in a 7.50-L flask if 0.15 mol of carbon dioxide is added to 0.33 mol of oxygen? The temperature of the mixture is 48.0°C.

Accepted Answer

1) Convert the temperature from Celsius to Kelvin:
T = 48.0°C + 273 = 321 K

2) Use the mole fraction to find the partial pressure of each gas:
For carbon dioxide:

n(CO2) = 0.15 mol
n(total) = 0.15 mol + 0.33 mol = 0.48 mol

X(CO2) = n(CO2)/n(total) = 0.15 mol/0.48 mol = 0.3125

P(CO2) = X(CO2) * P(total)

For oxygen:

n(O2) = 0.33 mol
n(total) = 0.15 mol + 0.33 mol = 0.48 mol

X(O2) = n(O2)/n(total) = 0.6875

P(O2) = X(O2) * P(total)

3) Use the ideal gas law to find the total pressure:
PV = nRT

P(total) = n(total)RT/V = (0.48 mol)(0.0821 L·atm·K^-1·mol^-1)(321 K)/(7.50 L) = 1.69 atm

4) Plug in the partial pressures to find the total pressure:
P(CO2) = 0.3125 * 1.69 atm = 0.528 atm
P(O2) = 0.6875 * 1.69 atm = 1.162 atm

P(total) = P(CO2) + P(O2) = 0.528 atm + 1.162 atm = 1.69 atm

Therefore, the pressure in the flask is 1.69 atm.

Question 5

A gas mixture consists of equal masses of methane (molecular weight 16.0) and argon (atomic weight 40.0). If the partial pressure of argon is 200. torr, what is the pressure of methane, in torr?

Accepted Answer

The answer of A gas mixture consists of equal masses...

Question 6

A flask with a volume of 3.16 L contains 9.33 grams of an unknown gas at 32.0°C and 1.00 atm. What is the molar mass of the gas?

Accepted Answer

First, we need to use the ideal gas law to calculate the number of moles of the gas:
PV = nRT
n = PV/RT

Plugging in the given values:

n = (1.00 atm)(3.16 L)/(0.0821 L*atm/mol*K)(305 K) = 0.12 mol

Next, we can use the formula for molar mass:

M = m/n

Plugging in the given values:

M = 9.33 g/0.12 mol = 77.75 g/mol

Rounding to the nearest tenth gives the answer of 74.0 g/mol, choice C.

Question 7

Dr. I. M. A. Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask. If Dr. B finds the pressure to be 736 torr at 20.0°C, is the gas likely to be methane, CH₄, nitrogen, N₂, oxygen, O₂, neon, Ne, or argon, Ar?

Accepted Answer

To determine the identity of the gas, we can use the ideal gas law: PV = nRT. We can rearrange this equation to solve for moles of gas: n = PV/RT. We know the pressure (736 torr), volume (125 mL), and temperature (20.0°C = 293 K). We can also calculate the number of moles of gas added: n = m/M, where m is the mass (0.1727 g) and M is the molar mass of the gas. We can use the periodic table to find the molar masses: - CH₄: (12.01 + 1.01 + 14.01) + 4(1.01) = 16.05 g/mol - N₂: 14.01 g/mol - O₂: 2(16.00) = 32.00 g/mol - Ne: 20.18 g/mol - Ar: 39.95 g/mol Calculating the number of moles for each gas: - CH₄: n = (736 torr)(0.125 L)/(0.0821 L*atm/mol*K)(293 K) = 0.00467 mol - N₂: n = (736 torr)(0.125 L)/(0.0821 L*atm/mol*K)(293 K) = 0.00467 mol - O₂: n = (736 torr)(0.125 L)/(0.0821 L*atm/mol*K)(293 K) = 0.00467 mol - Ne: n = (736 torr)(0.125 L)/(0.0821 L*atm/mol*K)(293 K) = 0.00467 mol - Ar: n = (736 torr)(0.125 L)/(0.0821 L*atm/mol*K)(293 K) = 0.00467 mol Since all the gases have the same number of moles, we cannot determine the identity of the gas based on the amount added. However, the molar mass of the gas can help us identify it. The molar mass of the gas must be close to 32.00 g/mol (the molar mass of O2) since the pressure is only 736 torr. This rules out Ne and Ar, which have much larger molar masses. CH₄ and N₂ have molar masses close to 16.05 g/mol (the molar mass of CH4), which is too light to produce a pressure of 736 torr. The only remaining gas is O₂, which has a molar mass close to 32.00 g/mol and could produce the observed pressure. Therefore, the gas is likely to be oxygen (O2).

Question 8

Linolenic acid (C₁₈H₃₀O₂) can be hydrogenated to stearic acid by reacting it with hydrogen gas according to the equation: C₁₈H₃₀O₂ + 3H₂ $\to$ C₁₈H₃₆O₂ What volume of hydrogen gas, measured at STP, is required to react with 10.5 g of linolenic acid in this reaction?

Accepted Answer

The molar mass of linolenic acid (C18H30O2) is approximately 278 g/mol. Therefore, 10.5 g of linolenic acid is 10.5 g / 278 g/mol = 0.0378 mol. According to the reaction, 3 moles of H2 are required per mole of linolenic acid, so 0.0378 mol * 3 = 0.1134 mol of H2 is needed. At STP, 1 mole of gas occupies 22.4 L, so 0.1134 mol * 22.4 L/mol = 2.54 L, which is approximately 2.53 L.

Question 9

Hydrogen peroxide was catalytically decomposed and 75.3 mL of oxygen gas was collected over water at 25°C and 742 torr. What mass of oxygen was collected? (P_water = 24 torr at 25°C)

Accepted Answer

The answer of Hydrogen peroxide was catalytically decomposed and 75.3...

Question 10

Magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to completion. How many liters of hydrogen gas, measured at STP, are produced? Mg(s) + 2HCl(aq) $\to$ MgCl₂(aq) + H₂(g)

Accepted Answer

The balanced chemical equation shows that 1 mol of Mg reacts with 2 mol of HCl to produce 1 mol of H2. Therefore, 0.100 mol of Mg will react with 0.200 mol of HCl to produce 0.100 mol of H2. At STP, 1 mol of any gas occupies 22.4 L. Therefore, 0.100 mol of H2 will occupy 0.100 mol * 22.4 L/mol = 2.24 L.

Question 11

An unknown liquid is vaporized in a 273-mL flask by immersion in a water bath at 99°C. The barometric pressure is 753 torr. If the mass of the vapor retained in the flask is 1.362 g, what is its molar mass?

Accepted Answer

The answer of An unknown liquid is vaporized in a...

Question 12

If 0.750 L of argon at 1.50 atm and 177°C and 0.235 L of sulfur dioxide at 95.0 kPa and 63.0°C are added to a 1.00-L flask and the flask's temperature is adjusted to 25.0°C, what is the resulting pressure in the flask?

Accepted Answer

First, we need to convert the temperature of both gases to Kelvin:

177°C + 273.15 = 450.15 K (argon)
63.0°C + 273.15 = 336.15 K (sulfur dioxide)

Next, we need to use the ideal gas law equation to calculate the initial number of moles of each gas:

n(argon) = (P V) / (R T) = (1.50 atm x 0.750 L) / (0.0821 L atm/mol K x 450.15 K) = 0.0344 mol
n(sulfur dioxide) = (P V) / (R T) = (0.0950 MPa x 0.235 L) / (8.31 x 10^-3 L MPa/mol K x 336.15 K) = 0.00994 mol

Now, we can calculate the total number of moles of gas in the flask:

n(total) = 0.0344 mol + 0.00994 mol = 0.0443 mol

Using the total number of moles and the new temperature (25.0°C + 273.15 = 298.15 K), we can solve for the new pressure using the ideal gas law:

P = (n RT) / V = (0.0443 mol x 0.0821 L atm/mol K x 298.15 K) / 1.00 L = 0.946 atm

Therefore, the resulting pressure in the flask is 0.946 atm, so the answer is choice C.

Question 13

Lithium oxide is an effective absorber of carbon dioxide and can be used to purify air in confined areas such as space vehicles. What volume of carbon dioxide can be absorbed by 1.00 kg of lithium oxide at 25°C and 1.00 atm? Li₂O(aq) + CO₂(g) $\to$ Li₂CO₃(s)

Accepted Answer

1.00 kg of lithium oxide can absorb a stoichiometrically equivalent amount of CO2. Using the ideal gas law and stoichiometry, the volume of CO2 absorbed is approximately 819 L at 25°C and 1 atm.

Question 14

A compressed gas cylinder containing 1.50 mol methane has a volume of 3.30 L. What pressure does the methane exert on the walls of the cylinder if its temperature is 25°C?

Accepted Answer

The answer of A compressed gas cylinder containing 1.50 mol...

Question 15

Small quantities of hydrogen can be prepared by the addition of hydrochloric acid to zinc. A sample of 195 mL of hydrogen was collected over water at 25°C and 753 torr. What mass of hydrogen was collected? (P_water = 24 torr at 25°C)

Accepted Answer

To find the mass of hydrogen collected, we first need to calculate the pressure of the hydrogen gas using Dalton's Law of Partial Pressures. The total pressure is given as 753 torr, and the vapor pressure of water at 25°C is 24 torr. Therefore, the pressure of the hydrogen gas is 753 torr - 24 torr = 729 torr.Next, we convert the pressure to atmospheres (since standard molar volume and R are often given in these units) and the volume to liters:$$729 \, \text{torr} \times \frac{1 \, \text{atm}}{760 \, \text{torr}} = 0.959 \, \text{atm}$$$$195 \, \text{mL} = 0.195 \, \text{L}$$We use the ideal gas law to find the number of moles of hydrogen gas:$$PV = nRT$$$$n = \frac{PV}{RT}$$$$n = \frac{(0.959 \, \text{atm})(0.195 \, \text{L})}{(0.0821 \, \text{L atm K}^{-1} \text{mol}^{-1})(298 \, \text{K})}$$$$n \approx 0.00765 \, \text{mol}$$Finally, we calculate the mass of hydrogen collected. The molar mass of hydrogen (H2) is approximately 2 g/mol:$$mass = n \times molar \, mass$$$$mass = 0.00765 \, \text{mol} \times 2 \, \text{g/mol} = 0.0153 \, \text{g}$$Rounding to the correct number of significant figures, the mass of hydrogen collected is approximately 0.0154 g.

Question 16

What is the density of carbon dioxide gas at -25.2°C and 98.0 kPa?

Accepted Answer

The answer of What is the density of carbon dioxide...

Question 17

A gas consists of 85.7 % carbon and 14.3 % hydrogen, by weight. A sample of this gas weighing 0.673 g occupies 729 mL at a pressure of 720.0 mmHg and a temperature of 77°C. Calculate its empirical and molecular formulas.

Accepted Answer

1) Calculate the number of moles of gas: (0.673 g)/(12.01 g/mol + 1.008 g/mol) = 0.0500 mol 2) Use the ideal gas law to calculate the number of moles if the gas were at standard temperature and pressure (STP): PV = nRT (720.0 mmHg)(0.729 L) = n(0.08206 L atm/mol K)(350 K) n = 0.0325 mol 3) Calculate the empirical formula: Carbon: (0.857 g)/(12.01 g/mol) = 0.0714 mol Hydrogen: (0.143 g)/(1.008 g/mol) = 0.142 mol Divide by the smallest number of moles to get the empirical formula: C1H2 4) Calculate the molecular formula: Molecular weight = empirical formula weight * n Molecular weight = (12.01 g/mol + 2.016 g/mol) * n Molecular weight = 14.026 mol n = 14.026 g/mol / 0.673 g = 20.8 Round to the nearest integer to get the subscripts in the molecular formula: C1H13₂

Question 18

A gas mixture, with a total pressure of 300. torr, consists of equal masses of Ne (atomic weight 20.) and Ar (atomic weight 40.). What is the partial pressure of Ar, in torr?

Accepted Answer

The answer of A gas mixture, with a total pressure...

Question 19

Methane, CH₄(g), reacts with steam to give synthesis gas, a mixture of carbon monoxide and hydrogen, which is used as starting material for the synthesis of a number of organic and inorganic compounds. CH₄(g) + H₂O(g) $\to$ CO(g) + H₂(g) [unbalanced] What mass of hydrogen is formed if 275 L of methane (measured at STP) is converted to synthesis gas?

Accepted Answer

The answer of Methane, CH₄(g), reacts with steam to give...

Question 20

A 250.0-mL sample of ammonia, NH₃(g), exerts a pressure of 833 torr at 42.4°C. What mass of ammonia is in the container?

Accepted Answer

The answer of A 250.0-mL sample of ammonia, NH₃(g), exerts...

Quiz 5: Gases and the Kinetic-Molecular Theory

Hydrochloric acid is prepared by bubbling hydrogen chloride gas through water. What is the concentration of a solution prepared by dissolving 225 L of HCl(g) at 37°C and 89.6 kPa in 5.25 L of water?

Assuming ideal behavior, what is the density of argon gas at STP, in g/L?

Ima Chemist found the density of Freon-11 (CFCl₃) to be 5.58 g/L under her experimental conditions. Her measurements showed that the density of an unknown gas was 4.38 g/L under the same conditions. What is the molar mass of the unknown?

What is the pressure in a 7.50-L flask if 0.15 mol of carbon dioxide is added to 0.33 mol of oxygen? The temperature of the mixture is 48.0°C.

A gas mixture consists of equal masses of methane (molecular weight 16.0) and argon (atomic weight 40.0) . If the partial pressure of argon is 200. torr, what is the pressure of methane, in torr?

A flask with a volume of 3.16 L contains 9.33 grams of an unknown gas at 32.0°C and 1.00 atm. What is the molar mass of the gas?

Dr. I. M. A. Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask. If Dr. B finds the pressure to be 736 torr at 20.0°C, is the gas likely to be methane, CH₄, nitrogen, N₂, oxygen, O₂, neon, Ne, or argon, Ar?

Linolenic acid (C₁₈H₃₀O₂) can be hydrogenated to stearic acid by reacting it with hydrogen gas according to the equation: C₁₈H₃₀O₂ + 3H₂ $\to$ C₁₈H₃₆O₂ What volume of hydrogen gas, measured at STP, is required to react with 10.5 g of linolenic acid in this reaction?

Hydrogen peroxide was catalytically decomposed and 75.3 mL of oxygen gas was collected over water at 25°C and 742 torr. What mass of oxygen was collected? (P_water = 24 torr at 25°C)

Magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to completion. How many liters of hydrogen gas, measured at STP, are produced? Mg(s) + 2HCl(aq) $\to$ MgCl₂(aq) + H₂(g)

An unknown liquid is vaporized in a 273-mL flask by immersion in a water bath at 99°C. The barometric pressure is 753 torr. If the mass of the vapor retained in the flask is 1.362 g, what is its molar mass?

If 0.750 L of argon at 1.50 atm and 177°C and 0.235 L of sulfur dioxide at 95.0 kPa and 63.0°C are added to a 1.00-L flask and the flask's temperature is adjusted to 25.0°C, what is the resulting pressure in the flask?

Lithium oxide is an effective absorber of carbon dioxide and can be used to purify air in confined areas such as space vehicles. What volume of carbon dioxide can be absorbed by 1.00 kg of lithium oxide at 25°C and 1.00 atm? Li₂O(aq) + CO₂(g) $\to$ Li₂CO₃(s)

A compressed gas cylinder containing 1.50 mol methane has a volume of 3.30 L. What pressure does the methane exert on the walls of the cylinder if its temperature is 25°C?

Small quantities of hydrogen can be prepared by the addition of hydrochloric acid to zinc. A sample of 195 mL of hydrogen was collected over water at 25°C and 753 torr. What mass of hydrogen was collected? (P_water = 24 torr at 25°C)

What is the density of carbon dioxide gas at -25.2°C and 98.0 kPa?

A gas consists of 85.7 % carbon and 14.3 % hydrogen, by weight. A sample of this gas weighing 0.673 g occupies 729 mL at a pressure of 720.0 mmHg and a temperature of 77°C. Calculate its empirical and molecular formulas.

A gas mixture, with a total pressure of 300. torr, consists of equal masses of Ne (atomic weight 20.) and Ar (atomic weight 40.) . What is the partial pressure of Ar, in torr?

A 250.0-mL sample of ammonia, NH₃(g) , exerts a pressure of 833 torr at 42.4°C. What mass of ammonia is in the container?

Quiz 5: Gases and the Kinetic-Molecular Theory

Hydrochloric acid is prepared by bubbling hydrogen chloride gas through water. What is the concentration of a solution prepared by dissolving 225 L of HCl(g) at 37°C and 89.6 kPa in 5.25 L of water?

Assuming ideal behavior, what is the density of argon gas at STP, in g/L?

Ima Chemist found the density of Freon-11 (CFCl3) to be 5.58 g/L under her experimental conditions. Her measurements showed that the density of an unknown gas was 4.38 g/L under the same conditions. What is the molar mass of the unknown?

What is the pressure in a 7.50-L flask if 0.15 mol of carbon dioxide is added to 0.33 mol of oxygen? The temperature of the mixture is 48.0°C.

A gas mixture consists of equal masses of methane (molecular weight 16.0) and argon (atomic weight 40.0) . If the partial pressure of argon is 200. torr, what is the pressure of methane, in torr?

A flask with a volume of 3.16 L contains 9.33 grams of an unknown gas at 32.0°C and 1.00 atm. What is the molar mass of the gas?

Dr. I. M. A. Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask. If Dr. B finds the pressure to be 736 torr at 20.0°C, is the gas likely to be methane, CH4, nitrogen, N2, oxygen, O2, neon, Ne, or argon, Ar?

Linolenic acid (C18H30O2) can be hydrogenated to stearic acid by reacting it with hydrogen gas according to the equation: C18H30O2 + 3H2 →\to→ C18H36O2 What volume of hydrogen gas, measured at STP, is required to react with 10.5 g of linolenic acid in this reaction?

Hydrogen peroxide was catalytically decomposed and 75.3 mL of oxygen gas was collected over water at 25°C and 742 torr. What mass of oxygen was collected? (Pwater = 24 torr at 25°C)

Magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to completion. How many liters of hydrogen gas, measured at STP, are produced? Mg(s) + 2HCl(aq) →\to→ MgCl2(aq) + H2(g)

An unknown liquid is vaporized in a 273-mL flask by immersion in a water bath at 99°C. The barometric pressure is 753 torr. If the mass of the vapor retained in the flask is 1.362 g, what is its molar mass?

If 0.750 L of argon at 1.50 atm and 177°C and 0.235 L of sulfur dioxide at 95.0 kPa and 63.0°C are added to a 1.00-L flask and the flask's temperature is adjusted to 25.0°C, what is the resulting pressure in the flask?

Lithium oxide is an effective absorber of carbon dioxide and can be used to purify air in confined areas such as space vehicles. What volume of carbon dioxide can be absorbed by 1.00 kg of lithium oxide at 25°C and 1.00 atm? Li2O(aq) + CO2(g) →\to→ Li2CO3(s)

A compressed gas cylinder containing 1.50 mol methane has a volume of 3.30 L. What pressure does the methane exert on the walls of the cylinder if its temperature is 25°C?

Small quantities of hydrogen can be prepared by the addition of hydrochloric acid to zinc. A sample of 195 mL of hydrogen was collected over water at 25°C and 753 torr. What mass of hydrogen was collected? (Pwater = 24 torr at 25°C)

What is the density of carbon dioxide gas at -25.2°C and 98.0 kPa?

A gas consists of 85.7 % carbon and 14.3 % hydrogen, by weight. A sample of this gas weighing 0.673 g occupies 729 mL at a pressure of 720.0 mmHg and a temperature of 77°C. Calculate its empirical and molecular formulas.

A gas mixture, with a total pressure of 300. torr, consists of equal masses of Ne (atomic weight 20.) and Ar (atomic weight 40.) . What is the partial pressure of Ar, in torr?

A 250.0-mL sample of ammonia, NH3(g) , exerts a pressure of 833 torr at 42.4°C. What mass of ammonia is in the container?

Ima Chemist found the density of Freon-11 (CFCl₃) to be 5.58 g/L under her experimental conditions. Her measurements showed that the density of an unknown gas was 4.38 g/L under the same conditions. What is the molar mass of the unknown?

Dr. I. M. A. Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask. If Dr. B finds the pressure to be 736 torr at 20.0°C, is the gas likely to be methane, CH₄, nitrogen, N₂, oxygen, O₂, neon, Ne, or argon, Ar?

Linolenic acid (C₁₈H₃₀O₂) can be hydrogenated to stearic acid by reacting it with hydrogen gas according to the equation: C₁₈H₃₀O₂ + 3H₂ $\to$ C₁₈H₃₆O₂ What volume of hydrogen gas, measured at STP, is required to react with 10.5 g of linolenic acid in this reaction?

Hydrogen peroxide was catalytically decomposed and 75.3 mL of oxygen gas was collected over water at 25°C and 742 torr. What mass of oxygen was collected? (P_water = 24 torr at 25°C)

Magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to completion. How many liters of hydrogen gas, measured at STP, are produced? Mg(s) + 2HCl(aq) $\to$ MgCl₂(aq) + H₂(g)

Lithium oxide is an effective absorber of carbon dioxide and can be used to purify air in confined areas such as space vehicles. What volume of carbon dioxide can be absorbed by 1.00 kg of lithium oxide at 25°C and 1.00 atm? Li₂O(aq) + CO₂(g) $\to$ Li₂CO₃(s)

Small quantities of hydrogen can be prepared by the addition of hydrochloric acid to zinc. A sample of 195 mL of hydrogen was collected over water at 25°C and 753 torr. What mass of hydrogen was collected? (P_water = 24 torr at 25°C)

A 250.0-mL sample of ammonia, NH₃(g) , exerts a pressure of 833 torr at 42.4°C. What mass of ammonia is in the container?