ch 8 - gases

Question 1

pressure

Answer 1

force exerted per unit area;
F / A

Question 2

barometer

Answer 2

device used to measure atmospheric pressure

Question 3

ideal gas

Answer 3

hypothetical gas whose physical properties are perfectly described by the gas laws

Question 4

STP

Answer 4

273.15º K / 0º C
1 atm / 101.305 kPa
22.4 L / 1 mol

Question 5

law of combining volumes

Answer 5

when gases combine at STP, the ratios are always in the value of whole numbers

Question 6

partial pressure

Answer 6

pressure exerted by an individual gas in a mixture

Question 7

mole fraction

Answer 7

concentration unit defined as the ratio of the molar amount of a mixture component to the total number of moles of all mixture components;
X = nP / nT

Question 8

vapor pressure

Answer 8

pressure exerted by vapor in equilibrium with liquid in a closed container at a specific pressure

Question 9

kinetic molecular theory

Answer 9

theory to explain ideal gas behavior:

1. Gas molecules move in straight lines, changing course when they collide with something
2. Gas molecules are negligibly small compared to the distances between them
3. The pressure exerted by a gas in a container results from collisions between the gas molecules and the container walls
4. Gas molecules exert no attractive or repulsive forces on each other or the container walls; therefore, their collisions are elastic
5. The average kinetic energy of the gas molecules is proportional to the kelvin temperature of the gas