The Gas Laws Unit: Test - 96%

If 6.00 g of carbon is burned completely, what volume of carbon dioxide gas is released at STP?

11.2 L

What volume would 3.01•1023 molecules of oxygen gas occupy at STP?

11.2 L

Consider this reaction. mc030-1.jpg What volume (in milliliters) of oxygen gas is required to react with 4.03 g of Mg at STP?

1860 mL

What is the temperature of 0.80 mol of a gas stored in a 275 mL cylinder at 175 kPa?

7.2 K

A gas has experienced a small increase in volume but has maintained the same pressure and number of moles. According to the ideal gas law, how has the temperature of the gas changed?

It has increased slightly.

A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia?

0.36 atm

Which gas occupies the highest volume at STP?

2 mol of H2

Consider the reaction. mc014-1.jpg How many grams of methane should be burned in an excess of oxygen at STP to obtain 5.6 L of carbon dioxide?

4.0 g

If two gases are present in a container, the total pressure in the container is equal to

he sum of the pressures that are exerted by each of the two gases.

Which law relates temperature, pressure, volume, and the number of moles of a gas under perfect conditions?

ideal gas law

Five gases combined in a gas cylinder have the following partial pressures: 3.00 atm (N2), 1.80 atm (O2), 0.29 atm (Ar), 0.18 atm (He), and 0.10 atm (H). What is the total pressure that is exerted by the gases?

5.37 atm

Magnesium reacts with hydrochloric acid (HCl) as follows. mc025-1.jpg How many milliliters of hydrogen gas are produced by the reaction 0.020 mol of magnesium with excess of hydrochloric acid at STP?

450 mL

According to the equation 2Na + 2H2O mc012-1.jpg 2NaOH+H2, what mass of Na is required to yield 22.4 L of H2 at STP? (The atomic mass of Na is 22.99 u.)

46.0 g

Consider the reaction. mc015-1.jpg How many grams of N2 are required to produce 100.0 L of NH3 at STP?

62.5 g

Consider the reaction. mc028-1.jpg Which statement is true at STP? (The atomic mass of Zn is 65.39 u.)

65.39 g of Zn produce 22.4 L of H2 gas.

Which laws can be combined to form the ideal gas law?

Charles's law, Avogadro's law, and Boyle's law

The absolute temperature of a gas is increased four times while maintaining a constant volume. What happens to the pressure of the gas?

It increases by a factor of four.

The volume of a gas decreases to half of its original volume, but the gas maintains the same number of moles and temperature. According to the ideal gas law, what will most likely happen to the pressure?

It will double.

If a gas is moved from a large container to a small container but its temperature and number of moles remain the same, what would happen to the pressure of the gas?

It would increase.

If the pressure of a 2.00 L sample of gas is 50.0 kPa, what pressure does the gas exert if its volume is decreased to 20.0 mL? Which equation should you use? What is the new pressure?

P1V1 = P2V2 5000 kPa

Which proportionality shows the result of combining Avogadro's law with Boyle's law?

V = n/P

Which equation is derived from the combined gas law?

V1/T1 = V2/T2

Consider the proportionality below. PV -> nT What does this best represent?

ideal gas law

Which best defines partial pressure in a mixture of gases?

pressure that is exerted by one gas as if it occupied a container by itself

The gas in the piston is at constant temperature. A student increases the pressure on the piston from 2 atm to 3 atm. The observation will be summarized in a row of the incomplete table below. Which row of the table and which observation would the student fill?

row 1, volume decreases when pressure increases

The gas in the piston is being heated, and the piston has moved upward. The observation will be summarized in a row of the incomplete table below. What are the variables for this piston?

temperature and volume

Which correctly defines molar volume of an ideal gas?

the volume that is occupied by 1 mol of an ideal gas at STP, which is 22.4 L

Consider the equation. mc016-1.jpg Which represents the correct mass-volume relationship at STP?

32.00 g of O2 react with an excess of H2 to produce (2 ´ 22.4) L of H2O.

Consider a balloon with volume V. It contains n moles of gas and has an internal pressure of P. The temperature of the gas is T. The balloon is placed in a freezer at temperature 0.75T. The freezer is pressurized at 1.25P. Which of these could be the final volume of the balloon? The balloon is removed from the freezer and returned to its initial conditions. It is then heated to a temperature of 2T at a pressure of 2P. How does the volume of the balloon change? If the number of moles of gas increases to 1.5n, what is the new volume if pressure and temperature are held constant?

0.60 V it does not change 1.5V

A tire at 21°C has a pressure of 0.82 atm. Its temperature decreases to -3.5°C. If there is no volume change in the tire, what is the pressure after the temperature change?

0.75 atm

Which law states that the volume and absolute temperature of a fixed quantity of gas are directly proportional under constant pressure conditions?

Charles's law

The incomplete table below shows selected characteristics of gas laws. Which constants would most likely be filled in the first row of the table?

temperature and moles of gas

Complete the table by filling in the missing information.

A - pressure, volume B - temperature, moles of gas C - Charles's law D - V = kT E - temperature, pressure F - P = kT G - number of moles only

Which law states that the pressure and absolute temperature of a fixed quantity of gas are directly proportional under constant volume conditions?

Charles's law

Magnesium chloride, MgCl2(s) reacts with water vapor to form magnesium oxide, MgO(s) and HCl(g). What is the balanced chemical equation for this reaction? When magnesium chloride reacts with water, 5.85 L HCl(g) is produced. molar mass of HCl = 36.5 g/mol molar mass of MgCl2 = 95.2 g/mol How many moles of HCl was produced? How many moles of MgCl2 reacted? What mass of MgCl2 reacted?

MgCl2(s) + H2O(g) mc001-3.jpg MgO(s) + 2HCl(g) 0.261 moles of HCl 0.131 moles of MgCl2 12.4 g MgCl2

Sulfur trioxide, SO3(g), reacts with water to form sulfuric acid, H2SO4(g), a major component of volcanic smog. What is the balanced chemical equation for this reaction?

SO3(g) + H2O(g) mc001-2.jpg H2SO4(g)

Which statement can best be concluded from the ideal gas law?

The product of pressure and volume of an ideal gas is proportional to the absolute temperature.

A student uses 0.0821 L• atm/mol • K as the value of the gas constant. What is most likely true about the variables in the ideal gas law?

V has the units of liters, and T has the units of kelvin.

Identify all of the gas law equations that relate to the ideal gas law.

V1/T1 = V2/T2 V1/n1 = V2/n2 P1V1 = P2V2 P1/T1 = P2/T2

Consider the proportionality below. mc009-1.jpg What does this best represent?

ideal gas law

When hot lava reaches seawater, the salts in the water react with steam to form gaseous hydrochloric acid. You are given an unbalanced chemical equation for one such reaction and the volume of HCl(g) produced. Explain how you would find the mass of solid sea salt needed to produce the given gas volume.

First, I would balance the chemical equation. I would convert the volume of HCl to mol HCl by dividing by the molar volume. Next, I would use the balanced equation to find out how many moles of the salt are needed to produce the moles of HCl. Finally, I would multiply by the molar mass of the salt to convert moles to mass.

How will the volume of a gas be affected if the pressure is tripled, but the temperature remains the same? Why might a rubber raft burst if it is left in the sun on a summer day?

it is decreased to one third of its original volume temperature increases, causing interior pressure to increase

If you decreased the volume of a sample of gas by a factor of three while maintaining a constant pressure, how would the absolute temperature of the gas be affected? A gas at 300 K and 4.0 atm is moved to a new location with a temperature of 250 K. The volume changes from 5.5 L to 2.0 L. What is the pressure of the gas at the new location? What is the partial pressure of 0.50 mol Ne gas combined with 1.20 mol Kr gas at a final pressure of 730 torr?

it would decrease threefold 9.2 atm 215 torr

The table below shows a comparison of the different gas laws. Some cells have been left blank. Which are assumed to be constant while using the combined gas law?

number of moles

A scientist is measuring the pressure that is exerted by each of the following gases in the atmosphere: carbon dioxide, oxygen, and nitrogen. Which term most likely describes what she is measuring?

partial pressure

The ideal gas constant, R has several different values that could be used. Which quantity causes these differences?

pressure

The incomplete table below shows selected characteristics of gas laws. What are the variables in Gay-Lussac's law?

pressure and temperature

If the pressure, volume, and the number of moles of a gas are known, which is needed to calculate the universal gas constant from the ideal gas law?

the temperature of the gas

Propane (C3H8), a fuel that is used in camp stoves, produces carbon dioxide (CO2) and water vapor (H2O) on combustion as follows. mc032-1.jpg Given that the molar mass of H2O is 18.02 g/mol, how many liters of propane are required at STP to produce 75 g of H2O from this reaction?

23 L

Which law is based on the graph that is shown below?

Boyle's law

The pressure of 1 mol of gas is decreased to 0.5 atm at 273 K. What happens to the molar volume of the gas under these conditions?

The molar volume is doubled

If the pressure, volume, and temperature of a gas are known, which can most likely be found by using the ideal gas law?

the molar amount of the gas

A gas cylinder contains 2.0 mol of gas X and 6.0 mol of gas Y at a total pressure of 2.1 atm. What is the partial pressure of gas Y?

1.6 atm

A balloon that had a volume of 3.50 L at 25.0°C is placed in a hot room at 40.0°C. If the pressure remains constant at 1.00 atm, what is the new volume of the balloon in the hot room?

3.68 L

Which law is described by saying that when the pressure of a gas in a sealed container is cut in half, the gas will double in volume at a steady temperature?

Boyle's law

Which law relates to the ideal gas law?

V1/n1 = V2/n2

A and B are two gases that are mixed together; 2.50 mol A is mixed with 0.85 mol B. If the final pressure of the mixture is 1.75 atm, what are the partial pressures of A and B? Suppose that 0.25 mole of gas C was added to the mixture without changing the total pressure of the mixture. How does the addition of C to the mixture change the mole fraction of gas A? How does the addition of C to the mixture change the partial pressure of gas A? What is the partial pressure of C?

1.31 atm A 0.44 atm B decreases it decreases it 0.12 atm C

A balloon contains 1.00 mol helium gas at STP. What will the volume of the balloon be if the pressure increases to 2.00 atm? A syringe contains 0.10 mol neon gas at STP. What volume does the syringe indicate? A chemist adds 0.10 mol argon gas to the syringe. The pressure and temperature remain constant. What will be the volume on the syringe after the argon is added?

11.2 L 2.24 L 4.48 L

The molar volume of a gas at STP, in liters, is You can use the molar volume to convert 2 mol of any gas to You can also use the molar volume to convert 11.2 L of any gas to Avogadro's law tells you that 1.2 L of O2(g) and 1.2 L of NO2(g) are ________ numbers of moles of gas. Sulfur dioxide gas, SO2(g), is released from active volcanoes. It reacts in the atmosphere to form sulfur trioxide, SO3(g). 2SO2(g) + O2(g) → 2SO3(g) Which statement(s) best describes the reaction? Check all that apply.

22.4 44.8 L 0.500 mol the same The reaction is balanced. The coefficients can represent moles, molecules, or liters.

Acetylene gas (C2H2) reacts with oxygen gas (O2) to produce carbon dioxide (CO2) and water vapor (H2O). How many liters of C2H2 are required to produce 75.0 L of CO2? What volume of H2O is produced? What volume of O2 is required? When making the calculations, did you need to find the number of moles? Liquid carbon disulfide (CS2) reacts with 44.8 L O2 gas to produce the gases carbon dioxide (CO2) and sulfur dioxide (SO2) What is the mass of carbon dioxide produced? What is the mass of sulfur dioxide produced? When making the calculations, did you need to find the number of moles?

37.5 L 37.5 L 93.8 L no 29.3g 85.4g yes

The gases listed are at standard temperature and pressure: · 1 mol of CO2 gas · 1 mol of N2 gas · 2 mol of O2 gas Which statement is correct?

The volumes of 1 mol of CO2 and 1 mol of N2 gases are the same.

Shana solves stoichiometry problems using the equation for the synthesis of water. 2H2(g) + O2(G) -> 2H2O(g) Which interpretation of the balanced equation would cause Shana to make a mistake?

Two grams of hydrogen react with one gram of oxygen to form two grams of water.

Determine the number of moles of air present in 1.35 L at 750 torr and 17.0°C. Which equation should you use? What is the number of moles present? A sample of N2 gas occupying 800.0 mL at 20.0°C is chilled on ice to 0.00°C. If the pressure also drops from 1.50 atm to 1.20 atm, what is the final volume of the gas? Which equation should you use? What is the final volume of the gas?

n = PV/RT 0.056 mol V2 = P1V1T2/P2T1 932 mL

The gas in the piston is being heated, and the piston has moved upward. The observation will be summarized in a row of the incomplete table below. mc023-1.jpg What are the variables for this piston?

temperature and volume

What is the temperature in kelvin of a gas if it is allowed to expand from 1.50 L to 4.50 L? The initial temperature is 10.0°C and pressure is constant throughout the change. Which equation should you use? What is the final temperature?

T2 = (V2/V1)T1 849 K

Consider the reaction. 3Mg(s) + 2H3PO4(aq) -> Mg3(PO4)2(s) + 3H2(g) Which statement is true at STP? (The atomic mass of Mg is 24.31 u.)

(3 x 24.31) g of Mg produce (3 x 22.4) L of H2 gas.

The volume of a gas is 450 mL when its pressure is 1.00 atm. If the temperature of the gas does not change, what is the pressure when its volume is changed to 2.00 L?

0.225 atm

Consider the reaction. C(s) + O2(g) -> CO2(g) How many grams of carbon should be burned in an excess of oxygen at STP to obtain 2.21 L of carbon dioxide?

1.18 g

How many moles of oxygen (O2) are present in 33.6 L of the gas at 1 atm and 0°C?

1.5

What is the molar volume of a gas at standard temperature and pressure?

22.4 L

What is the volume of 0.200 mol of an ideal gas at 200. kPa and 400. K?

3.33 L

Which law states that the volume of a gas is proportional to the moles of the gas when pressure and temperature are kept constant?

Avogadro's law

A child sits on a partially filled balloon and decreases the volume by half. What happens to the pressure inside of the balloon? For the same balloon, how does the density inside the balloon change? A scientist takes a small, partially inflated balloon out of liquid nitrogen (at a very low temperature). As the balloon rests on the table, it begins to grow in size. Which statement(s) best explains why the balloon grows?

It increases increases The air warms and increases particle movement. Increased particle movement leads to increased volume. Increased temperature means increased volume as long as the container is flexible.

At 35.0°C and 3.00 atm pressure, a gas has a volume of 1.40 L. What pressure does the gas have at 0.00°C and a volume of 0.950 L? Which equation should you use? What is the pressure of the gas? A balloon containing 0.500 mol Ar at 0.00°C and 65.0 kPa pressure is expanded by adding more argon. How many moles of argon are added to bring the sample to a final volume of 60.0 L at 30.0°C and 45.0 kPa? What is the original volume of the gas? How many moles of argon exist in the new conditions? How many moles of argon were added?

P2 = P1V1T2/T1V2 3.92 atm 17.5 L 1.07 mol 0.570 mol

Which describes the volume of 1 mol of gas at standard temperature and pressure?

The volume is the same for any gas.

Which proportionality applies to Avogadro's law?

V -> n

Charles's law Gay-Lussac's law Boyle's law

d b e

Which quantity is held constant when working with Boyle's, Charles's, and Gay-Lussac's laws?

moles

A balloon containing 0.0400 mol of a gas with a volume of 500 mL was expanded to 1.00 L. Answer the questions and round answers to nearest hundredth place. Which equation should you use to find the amount of gas added? What is the final number of moles?

n2 = V2n1/V1 0.08 mol