Chem Chapter 5

Gaseous chlorine is held in two separate containers at identical temperature and pressure. The volume of container 1 is 1.30 L, and it contains 6.70 mol of gas. The volume of container 2 is 2.33 L. How many moles of the gas are in container 2?

1.3/6.7 = 2.33/x === 12.0 mol

It is found that 250.0 mL of a gas at STP has a mass of 0.700 g. What is the molar mass?

0.7/((0.25 •1)/(0.08206)(273))

Consider a sample of gas in a container on a comfortable spring day. The Celsius temperature suddenly doubles, and you transfer the gas to a container with twice the volume of the first container. If the original pressure was 12 atm, what is a good estimate for the new pressure?

12(298)/1 = 323x/2 === 6.4 atm

What is the name for the lowest layer of the atmosphere, which is most influenced by human activities?

troposphere

A gas sample is heated from -20.0° C to 57.0°C and the volume is increased from 2.00 L to 4.50 L. If the initial pressure is 0.140 atm, what is the final pressure?

0.14(2)/253 = 4.5x/330 === 0.0811 atm

A balloon has a volume of 2.32 litres at 24.0° C. The balloon is heated yo 48.0° C. Calculate the new volume of the balloon.

2.32/297 = x/321 === 2.51 L

A plastic bag is weighed and then filled successively with two gases, X and Y. The following data are gathered: Temperature: 0.0° C (273 K) Pressure: 1.00 atmosphere Mass of empty bag: 20.77 g Mass of bag filled with gas X: 24.97 g Mass of 1.12 liters of air at conditions given: 1.30 g Volume of bag: 1.12 liter Molar volume at STP: 22.4 liters The molar mass of gas Y is

5.56(0.08206)(273)/1 === 125 g/mol

The partial pressures of CH4, N2, and O2 in a sample of gas were found to be 135 mmHg, 508 mmHg, and 571 mmHg, respectively. Calculate the mole fraction of nitrogen.

508/(135+508+571) === 0.418

A plastic bag is weighed and then filled successively with two gases, X and Y. The following data are gathered: Temperature: 0.0° C (273 K) Pressure: 1.00 atmosphere Mass of empty bag: 20.77 g Mass of bag filled with gas X: 24.97 g Mass of 1.12 liters of air at conditions given: 1.30 g Volume of bag: 1.12 liter Molar volume at STP: 22.4 liters The mass of 1.12 litres of gas Y is found to be 6.23 g. The density of gas Y is

6.23/1.12 === 5.56 g/L

A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 729 mm above the pool of mercury. what is the pressure of the atmosphere?

729/760 = 0.959 atm

Which of the following properties of a real gas is related to the b coefficient in the van der Waals equation?

Real gases consist of molecules or atoms that have volume.

Graham's Law states that:

The rates of effusion of gases are inversely proportional to the square roots of their molar masses.

Boyle's law states that:

The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature.

The van der Waals equation, nRT = [P + a(n/V)²](V-nb), incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of the corrections accounts for

the finite volume of molecules

Calculate the root mean square velocity for the O2 molecules in a sample of O2 gas at 11.8° C. (R=8.3145 J/K mol)

√(3)(8.3145)(284.8)/√0.032 === 471.2 m/s

Four identical 1.0 L flasks contain the games He, Cl2, CH4, and NH3, each at 0° C and 1 ATM pressure. For which gas do the molecules have the highest average velocity?

√3RT/√M === He

Calculate the ratio of the effusion rates of N2 and N2O.

√44.02/√28.02 === 1.25

A sample of oxygen gas has a volume of 1.72 L at 27° C and 800.0 torr. How many oxygen molecules does it contain?

(1.05)(1.72) = (n)(0.08206)(300) === 4.43 × 10²²

Which of the following is included as a postulate in the kinetic molecular theory of an ideal gas?

All collisions between molecules are elastic.

I are holding four identical balloons each containing 10.0 g of a different gas. The balloon containing which gas is the largest balloon?

All have the same volume.

Pressure is

defined as the force per unit area

Order the following in increasing rate of effusion: F2, Cl2, NO, NO2, CH4

Cl2 < NO2 < F2 < NO < CH4

A gaseous mixture containing 1.5 mol At and 3.5 mol CO2 has a total pressure of 7.3 atm. What is the partial pressure of CO2?

3.5/5 = x/7.3 === 5.1 atm

A gas sample is held at a constant pressure. The gas occupies 3.62 L of volume when the temperature is 21.6°. Determine the temperature at which the volume of the gas is 3.42 L.

3.62/294.6 = 3.42/T === 278K

Which of the following is not a postulate of the kinetic molecular theory?

Gas particles have most of their mass concentrated in the center of the atom.