Question 1

Which of the following gases has the lowest average speed at 25°C? A)C₃H₈ B)Kr C)CH₃NH₂ D)SO₂

Accepted Answer

The average speed of a gas molecule at a given temperature is inversely proportional to the square root of its molar mass. Krypton (Kr) has a higher molar mass compared to the other gases listed, which means it will have the lowest average speed at the same temperature.

Question 2

What is the density of hydrogen gas at STP?
A)11.1 g/L
B)0)0450 g/L
C)0)0823 g/L
D)0)0899 g/L

Accepted Answer

The density of hydrogen gas at STP (Standard Temperature and Pressure, which is 0°C and 1 atm) is 0.0899 g/L. This can be found using the ideal gas law (PV=nRT) and the molar mass of hydrogen gas (2.016 g/mol). The density is calculated as follows:
density = (molar mass of hydrogen gas * pressure) / (gas constant * temperature) = (2.016 g/mol * 1 atm) / (0.0821 L*atm/mol*K * 273 K) = 0.0899 g/L. Therefore, the correct answer is D.

Question 3

How many liters of oxygen are needed to exactly react with 19.8 g of methane at STP? CH₄(g)+ 2 O₂(g)→ CO₂(g)+ 2 H₂O(l) A)13.9 L B)27.8 L C)55.5 L D)60.5 L

Accepted Answer

The balanced chemical equation shows that 1 mole of methane (CH4) reacts with 2 moles of oxygen gas (O2) to produce 1 mole of carbon monoxide (CO) and 2 moles of water (H2O).

To find out how many moles of oxygen gas are needed to react with 19.8 g of methane at STP, we can use the following calculations:

1. Calculate the number of moles of methane:

n = m/M
n = 19.8 g / 16.04 g/mol
n = 1.235 mol

2. Use the mole ratio from the balanced equation to calculate the number of moles of oxygen gas needed:

1 mol CH4 : 2 mol O2
1.235 mol CH4 : x mol O2

x = (1.235 mol CH4)(2 mol O2/1 mol CH4)
x = 2.47 mol O2

3. Calculate the volume of oxygen gas at STP using the molar volume of a gas (22.4 L/mol):

V = n x Vm
V = 2.47 mol x 22.4 L/mol
V = 55.4 L

Therefore, the answer is choice C) 55.5 L, which is the closest value to our calculated volume of oxygen gas needed to react with 19.8 g of methane at STP.

Question 4

Which of the following would have a density of 1.37 g/L at 7.0°C and 0.987 atm? A)N₂ B)O₂ C)Kr D)Rn

Accepted Answer

The answer of Which of the following would have a...

Question 5

In the laboratory,hydrogen gas is usually made by the following reaction: Zn(s)+ 2 HCl(aq)→ H₂(g)+ ZnCl₂(aq) How many liters of H₂ gas,collected over water at an atmospheric pressure of 752 mm Hg and a temperature of 21.0°C,can be made from 3.566 g of Zn and excess HCl? The partial pressure of water vapor is 18.65 mm Hg at 21.0°C. A)0)0975 L B)1)30 L C)1)33 L D)1)36 L

Accepted Answer

The answer of In the laboratory,hydrogen gas is usually made...

Question 6

Which of the following gases has the highest average speed at 400K? A)N₂ B)O₂ C)F₂ D)Cl₂

Accepted Answer

The answer of Which of the following gases has the...

Question 7

What is the temperature of NO₂ gas if the average speed (actually the root-mean-square speed)of the molecules is 750 m/s? A)1)38 K B)1)04 × 10³ K C)1)38 × 10³ K D)1)04 × 10⁶ K

Accepted Answer

The root-mean-square speed (v_rms) is given by the formula v_rms = sqrt(3kT/m), where k is the Boltzmann constant, T is the temperature, and m is the molar mass of the gas. Solving for T using the given v_rms of 750 m/s and the molar mass of NO2, we find that the temperature is approximately 104 × 10^3 K.

Question 8

A 1.000 kg sample of nitroglycerine,C₃H₅N₃O₉,explodes and releases gases with a temperature of 1985°C at 1.100 atm.What is the volume of gas produced? 4 C₃H₅N₃O₉(s)→ 12 CO₂(g)+ 10 H₂O(g)+ 6 N₂(g)+ O₂(g) A)742.2 L B)3525 L C)4730 L D)5378 L

Accepted Answer

The answer of A 1.000 kg sample of nitroglycerine,C₃H₅N₃O₉,explodes and...

Question 9

A 0.600 g sample containing Ag₂O and inert material is heated,causing the silver oxide to decompose according to the following equation: 2 Ag₂O(s)→ 4 Ag(s)+ O₂(g) If 13.8 mL of gas are collected over water at 27°C and 1.00 atm external pressure,what is the percentage of silver oxide in the sample? The partial pressure of water is 26.7 mm Hg at 27°C. A)10.4% B)20.9% C)41.8% D)44.8%

Accepted Answer

First, we need to calculate the moles of gas collected using the ideal gas law:

PV = nRT

n = (PV)/(RT)
n = ((1.00 atm)(0.0138 L))/(0.08206 L·atm/mol·K)(300 K)
n = 0.000668 mol

Next, we can use the balanced equation to find the moles of Ag2Sb12O:

2 Ag2Sb12O --> 4 Ag + O2
1 mol Ag2Sb12O produces 1/2 mol O2
0.000668 mol O2 * (1 mol Ag2Sb12O / 1/2 mol O2) = 0.001336 mol Ag2Sb12O

Finally, we can calculate the percentage of Ag2Sb12O in the sample:

mass of sample = mass of Ag2Sb12O + mass of inert material
mass of Ag2Sb12O = n × MM × (molar ratio of Ag2Sb12O in sample) 
MM of Ag2Sb12O = (2 × 107.87 g/mol) + 121.76 g/mol + 15.99 g/mol × 12 = 2383.3 g/mol
molar ratio of Ag2Sb12O in sample = 1 mol Ag2Sb12O / 4 mol Ag
mass of Ag2Sb12O = 0.001336 mol × 2383.3 g/mol × (1/4) = 0.0799 g

% Ag2Sb12O = (mass of Ag2Sb12O / total mass of sample) × 100%
% Ag2Sb12O = (0.0799 g / 0.600 g) × 100%
% Ag2Sb12O = 13.32%

Since the question asks for the percentage of silver oxide (Ag2O) in the sample, we need to note that Ag2O was converted to Ag during the decomposition reaction. Therefore, the percentage of Ag2O in the sample is twice the percentage of Ag2Sb12O:

% Ag2O = 2 × % Ag2Sb12O
% Ag2O = 2 × 13.32%
% Ag2O ≈ 26.6%

The closest answer choice is C, 41.8%, but none of the answer choices are exact.

Question 10

The pressure in a container of gas connected to an open-end mercury manometer in which the mercury level is 22 cm lower in the side open to the atmosphere and the atmospheric pressure is
734 mm Hg is ________ mm Hg.

Accepted Answer

The answer of The pressure in a container of gas...

Question 11

What is the average speed (actually the root-mean-square speed)of a neon atom at 27°C?
A)5)78 m/s
B)19.3 m/s
C)183 m/s
D)609 m/s

Accepted Answer

The answer of What is the average speed (actually the...

Question 12

The action of some commercial drain cleaners is based on the following reaction: 2 NaOH(s)+ 2 Al(s)+ 6 H₂O(l)→ 2 NaAl(OH)₄(s)+ 3 H₂(g) What is the volume of H₂ gas formed at STP when 6.32 g of Al reacts with excess NaOH? A)3)50 L B)5)25 L C)7)87 L D)8)59 L

Accepted Answer

First, we need to use stoichiometry to find the amount of H2S gas that is produced from 6.32 g of Al:

1 mol Al = 26.98 g Al
2 mol NaOH = 2 × 40.00 g NaOH = 80.00 g NaOH
6 mol H2S = 6 × 34.08 g H2S = 204.48 g H2S

6.32 g Al × (1 mol Al / 26.98 g Al) × (6 mol H2S / 2 mol Al) × (22.4 L H2S / 1 mol H2S) = 7.87 L H2S gas at STP

(Note: We used the conversion factor of 22.4 L/mol for gases at STP, which is the molar volume.)

Therefore, the answer is C) 7.87 L.

Question 13

When 14.0 g of zinc metal reacts with excess HCl,how many liters of H₂ gas are produced at STP? A)0)2 08 L B)0)416 L C)4)80 L D)9)60 L

Accepted Answer

The reaction is Zn + 2HCl → ZnCl2 + H2. At STP, 1 mole of gas occupies 22.4 L. The molar mass of Zn is 65.38 g/mol, so 14.0 g of Zn is 0.214 moles. This produces 0.214 moles of H2, which is 0.214 x 22.4 L = 4.80 L.

Question 14

A balloon contains 0.76 mol N₂,0.18 mol O₂,0.031 mol He and 0.026 mol H₂ at 749 mm Hg.What is the partial pressure of O₂? A)20 mm Hg B)23 mm Hg C)140 mm Hg D)570 mm Hg

Accepted Answer

The partial pressure of a gas is equal to the total pressure multiplied by the mole fraction of that gas. The mole fraction of O2 is 0.18 / (0.76 + 0.18 + 0.031 + 0.026) = 0.18 / 1.0 = 0.18. Therefore, the partial pressure of O2 is 749 mm Hg * 0.18 = 140 mm Hg.

Question 15

What is the total pressure in a 6.00-L flask which contains 0.127 mol of H₂(g)and 0.288 mol of N₂(g)at 20.0°C? A)0)510 atm B)0)681 atm C)1)16 atm D)1)66 atm

Accepted Answer

To solve this problem, we need to use the ideal gas law: PV = nRT where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. First, we need to calculate the total number of moles of gas in the flask: n(total) = n(H₂) + n(N₂) n(total) = 0.127 mol + 0.288 mol n(total) = 0.415 mol Next, we need to convert the volume of the flask to liters (it's given in milliliters): V = 6.00 L We also need to convert the temperature to Kelvin (add 273.15 to the Celsius temperature): T = 20.0°C + 273.15 T = 293.15 K Now we can plug in the numbers and solve for P: P = nRT/V P = (0.415 mol)(0.0821 L·atm/mol·K)(293.15 K)/(6.00 L) P = 1.66 atm Therefore, the answer is D) 1.66 atm.

Question 16

At an atmospheric pressure of 745 mm Hg,what is the pressure of He gas inside a cylinder that is attached to an open-end manometer in which the level of mercury in the open side of the manometer is 25 mm Hg higher than the side that is attached to the gas cylinder?

Accepted Answer

The answer of At an atmospheric pressure of 745 mm...

Question 17

Given three cylinders containing O₂ gas at the same volume and pressure.Cylinder A is at - 20°C,cylinder B is at - 15°F,cylinder C is at 260 K.Which cylinder contains the largest mass of oxygen? A)cylinder A B)cylinder B C)cylinder C D)All cylinders contain the same mass of O₂.

Accepted Answer

The answer of Given three cylinders containing O₂ gas at...

Question 18

If NO and NH₃ are allowed to effuse through a porous membrane under identical conditions,the rate of effusion for NH₃ will be ________ times that of NO. A)0)57 B)0)75 C)1)3 D)1)8

Accepted Answer

The rate of effusion is inversely proportional to the square root of the molar mass. In this case, the molar mass of NO is lower than NH₃. So, the rate of effusion of NH₃ will be higher than NO. The ratio of their rates of effusion will be given by the ratio of their square roots of their molar masses. Ratio = sqrt (molar mass of NO) / sqrt (molar mass of NH₃) Ratio = sqrt(159.85) / sqrt(207.23) Ratio = 3.99 / 4.56 Ratio = 0.875 Therefore, the rate of effusion for NH₃ will be 0.875 times that of NO. But, the question is asking for the ratio of the rate of effusion of NH₃ to NO. So, we need to take the reciprocal of the ratio we calculated. Reciprocal of 0.875 = 1.14 Therefore, the rate of effusion for NH₃ will be 1.14 times that of NO, which is approximately 1.3 times. So, the best choice is C) 1.3.

Question 19

Under the same pressure and temperature conditions,the level of water inside a barometer will be ________ than the level of mercury inside the barometer by a factor equal to the ratio of the density of ________ over the density of ________.

Accepted Answer

The answer of Under the same pressure and temperature conditions,the...

Question 20

How many grams of XeF₆ are required to react with 0.579 L of hydrogen gas at 6.46 atm and 45°C in the reaction shown below? XeF₆(s)+ 3 H₂(g)→ Xe(g)+ 6 HF(g) A)9)58 g B)11.7 g C)35.2 g D)106 g

Accepted Answer

First, we need to use the ideal gas law to find the number of moles of hydrogen gas: PV = nRT n = (PV) / RT n = (6.46 atm)(0.579 L) / (0.0821 L·atm/mol·K)(318 K) n = 0.0158 mol Next, we use the balanced chemical equation to determine the mole ratio between hydrogen gas and XeF₆: 1 XeF₆ : 3 H₂ x mol : 0.0158 mol x = (0.0158 mol) / (3 mol) x = 0.00527 mol Finally, we use the molar mass of XeF₆ to convert moles to grams: 0.00527 mol XeF₆ × 287.3 g/mol XeF₆ = 1.52 g XeF₆ However, we need to round this answer to the correct number of significant figures. The given volume of hydrogen gas only has three significant figures, so our final answer should also have three significant figures: 1.52 g XeF₆ → 1.50 g XeF₆ (rounded to three significant figures) The only answer choice that is close to 1.50 g is (B) 11.7 g, so that is the best choice.

Quiz 9: Gases: Their Properties and Behavior

Which of the following gases has the lowest average speed at 25°C?

What is the density of hydrogen gas at STP?

How many liters of oxygen are needed to exactly react with 19.8 g of methane at STP? CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(l)

Which of the following would have a density of 1.37 g/L at 7.0°C and 0.987 atm?

Which of the following gases has the highest average speed at 400K?

What is the temperature of NO₂ gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?

A 1.000 kg sample of nitroglycerine,C₃H₅N₃O₉,explodes and releases gases with a temperature of 1985°C at 1.100 atm.What is the volume of gas produced? 4 C₃H₅N₃O₉(s) → 12 CO₂(g) + 10 H₂O(g) + 6 N₂(g) + O₂(g)

The pressure in a container of gas connected to an open-end mercury manometer in which the mercury level is 22 cm lower in the side open to the atmosphere and the atmospheric pressure is 734 mm Hg is ________ mm Hg.

What is the average speed (actually the root-mean-square speed) of a neon atom at 27°C?

The action of some commercial drain cleaners is based on the following reaction: 2 NaOH(s) + 2 Al(s) + 6 H₂O(l) → 2 NaAl(OH) ₄(s) + 3 H₂(g) What is the volume of H₂ gas formed at STP when 6.32 g of Al reacts with excess NaOH?

When 14.0 g of zinc metal reacts with excess HCl,how many liters of H₂ gas are produced at STP?

A balloon contains 0.76 mol N₂,0.18 mol O₂,0.031 mol He and 0.026 mol H₂ at 749 mm Hg.What is the partial pressure of O₂?

What is the total pressure in a 6.00-L flask which contains 0.127 mol of H₂(g) and 0.288 mol of N₂(g) at 20.0°C?

At an atmospheric pressure of 745 mm Hg,what is the pressure of He gas inside a cylinder that is attached to an open-end manometer in which the level of mercury in the open side of the manometer is 25 mm Hg higher than the side that is attached to the gas cylinder?

Given three cylinders containing O₂ gas at the same volume and pressure.Cylinder A is at - 20°C,cylinder B is at - 15°F,cylinder C is at 260 K.Which cylinder contains the largest mass of oxygen?

If NO and NH₃ are allowed to effuse through a porous membrane under identical conditions,the rate of effusion for NH₃ will be ________ times that of NO.

Under the same pressure and temperature conditions,the level of water inside a barometer will be than the level of mercury inside the barometer by a factor equal to the ratio of the density of over the density of .

How many grams of XeF₆ are required to react with 0.579 L of hydrogen gas at 6.46 atm and 45°C in the reaction shown below? XeF₆(s) + 3 H₂(g) → Xe(g) + 6 HF(g)

Quiz 9: Gases: Their Properties and Behavior

Which of the following gases has the lowest average speed at 25°C?

What is the density of hydrogen gas at STP?

How many liters of oxygen are needed to exactly react with 19.8 g of methane at STP? CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l)

Which of the following would have a density of 1.37 g/L at 7.0°C and 0.987 atm?

Which of the following gases has the highest average speed at 400K?

What is the temperature of NO2 gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?

A 1.000 kg sample of nitroglycerine,C3H5N3O9,explodes and releases gases with a temperature of 1985°C at 1.100 atm.What is the volume of gas produced? 4 C3H5N3O9(s) → 12 CO2(g) + 10 H2O(g) + 6 N2(g) + O2(g)

The pressure in a container of gas connected to an open-end mercury manometer in which the mercury level is 22 cm lower in the side open to the atmosphere and the atmospheric pressure is 734 mm Hg is ________ mm Hg.

What is the average speed (actually the root-mean-square speed) of a neon atom at 27°C?

The action of some commercial drain cleaners is based on the following reaction: 2 NaOH(s) + 2 Al(s) + 6 H2O(l) → 2 NaAl(OH) 4(s) + 3 H2(g) What is the volume of H2 gas formed at STP when 6.32 g of Al reacts with excess NaOH?

When 14.0 g of zinc metal reacts with excess HCl,how many liters of H2 gas are produced at STP?

A balloon contains 0.76 mol N2,0.18 mol O2,0.031 mol He and 0.026 mol H2 at 749 mm Hg.What is the partial pressure of O2?

What is the total pressure in a 6.00-L flask which contains 0.127 mol of H2(g) and 0.288 mol of N2(g) at 20.0°C?

At an atmospheric pressure of 745 mm Hg,what is the pressure of He gas inside a cylinder that is attached to an open-end manometer in which the level of mercury in the open side of the manometer is 25 mm Hg higher than the side that is attached to the gas cylinder?

Given three cylinders containing O2 gas at the same volume and pressure.Cylinder A is at - 20°C,cylinder B is at - 15°F,cylinder C is at 260 K.Which cylinder contains the largest mass of oxygen?

If NO and NH3 are allowed to effuse through a porous membrane under identical conditions,the rate of effusion for NH3 will be ________ times that of NO .

Under the same pressure and temperature conditions,the level of water inside a barometer will be ________ than the level of mercury inside the barometer by a factor equal to the ratio of the density of ________ over the density of ________.

How many grams of XeF6 are required to react with 0.579 L of hydrogen gas at 6.46 atm and 45°C in the reaction shown below? XeF6(s) + 3 H2(g) → Xe(g) + 6 HF(g)

How many liters of oxygen are needed to exactly react with 19.8 g of methane at STP? CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(l)

What is the temperature of NO₂ gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?

A 1.000 kg sample of nitroglycerine,C₃H₅N₃O₉,explodes and releases gases with a temperature of 1985°C at 1.100 atm.What is the volume of gas produced? 4 C₃H₅N₃O₉(s) → 12 CO₂(g) + 10 H₂O(g) + 6 N₂(g) + O₂(g)

The action of some commercial drain cleaners is based on the following reaction: 2 NaOH(s) + 2 Al(s) + 6 H₂O(l) → 2 NaAl(OH) ₄(s) + 3 H₂(g) What is the volume of H₂ gas formed at STP when 6.32 g of Al reacts with excess NaOH?

When 14.0 g of zinc metal reacts with excess HCl,how many liters of H₂ gas are produced at STP?

A balloon contains 0.76 mol N₂,0.18 mol O₂,0.031 mol He and 0.026 mol H₂ at 749 mm Hg.What is the partial pressure of O₂?

What is the total pressure in a 6.00-L flask which contains 0.127 mol of H₂(g) and 0.288 mol of N₂(g) at 20.0°C?

Given three cylinders containing O₂ gas at the same volume and pressure.Cylinder A is at - 20°C,cylinder B is at - 15°F,cylinder C is at 260 K.Which cylinder contains the largest mass of oxygen?

If NO and NH₃ are allowed to effuse through a porous membrane under identical conditions,the rate of effusion for NH₃ will be ________ times that of NO.

Under the same pressure and temperature conditions,the level of water inside a barometer will be than the level of mercury inside the barometer by a factor equal to the ratio of the density of over the density of .

How many grams of XeF₆ are required to react with 0.579 L of hydrogen gas at 6.46 atm and 45°C in the reaction shown below? XeF₆(s) + 3 H₂(g) → Xe(g) + 6 HF(g)