Chapter 10 - Gases

Question 0

What is pressure?

Answer 0

Force divided by area

Question 1

What are vapors?

Answer 1

The gaseous state of a substance that is normally a solid or liquid.

Question 2

What is the SI unit for pressure?

Answer 2

Pascal. 1 Pa = 1 N/m^2

Question 3

How many pascals are in a bar?

Answer 3

10^5 Pa = 1 bar

Question 4

What is an atmosphere (atm)?

Answer 4

A unit of pressure measurement. 1 ATM = 101325 Pa

Question 5

What is a torr?

Answer 5

A unit of pressure measurement. 760 torr=1 ATM

Question 6

What is a barometer?

Answer 6

A tool used to measure atmospheric pressure.

Question 7

What is a manometer?

Answer 7

A tool used to measure the pressure of enclosed gases.

Question 8

What is Boyle’s law?

Answer 8

For a constant quantity of gas at constant temperature, the volume of the gas is inversely proportional to the pressure.

P1V1=P2V2

Question 9

What is Charles’s law?

Answer 9

For a fixed quantity of gas at constant pressure, the volume is directly proportional to its absolute temperature.

V1/T1=V2/T2

Question 10

What is Avogadro’s hypothesis?

Answer 10

Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.

Question 11

What is Avogadro’s law?

Answer 11

For a gas at constant temperature and pressure, the volume of the gas is directly proportional to the number of moles of gas.

V1/N1=V2/N2

Question 12

What is the ideal gas equation?

Answer 12

PV=nRT

Question 13

What does the letter R represent in the ideal gas equation?

Answer 13

The gas constant.

R=.0821 LATM/MOLK

Question 14

What is the standard temperature and pressure?

Answer 14

0° C and 1 ATM

Question 15

What is Dalton’s law of partial pressures?

Answer 15

In gas mixtures, the total pressure is the sum of the partial pressures that each gas would exert if it were present alone under the same conditions.

Question 16

What is a partial pressure?

Answer 16

The partial pressure of a component of a mixture is equal to its mole fraction times the total pressure.

P1=X1P1

X is the mole fraction.

Question 17

What is a mole fraction?

Answer 17

It is the ratios of the moles of one component of a mixture to the total moles of all components.

Question 18

What is the kinetic-molecular theory of gases?

Answer 18

It accounts for the properties of an ideal gas in terms of a set of statements about the nature of gases.
These statements are as follows:
-Molecules are in continuous chaotic motion.
-The volume of gas molecules is negligible compared to the volume of their container.
-The gas molecules neither attract nor repel each other.
-The average kinetic energy of the gas molecules is proportional to the absolute temperature and does not change if temperature remains constant.

Question 19

What is the root-mean-square speed?

Answer 19

It varies in proportion to the square root of the absolute temperature and with the square root of the molar mass.

Question 20

What is effusion?

Answer 20

When gas molecules escape through a tiny hole.

Question 21

What is diffusion?

Answer 21

It is the spread of one substance throughout a space or throughout a second substance.

Question 22

What is a mean free path?

Answer 22

The average distance traveled by molecules between collisions.

Question 23

Why do real gases depart from ideal behavior?

Answer 23

1. The molecules possess finite volume.

2. The molecules experience attractive forces for one another.

Question 24

What is the van der Waals equation?

Answer 24

It is an equation of state for gases, which modifies the ideal gas equation to account for intrinsic molecular volume and intermolecular forces.