Chemistry - Ch 10

Question 1

Vapors

Answer 1

substances that are liquids or solids under ordinary conditions that can also exist in the gaseous state

Question 2

Pressure

Answer 2

conveys the idea of a force, a push that tends to move something in a given direction; = force/area

Question 3

pascal (Pa)

Answer 3

SI unit of pressure (N/m^2)

Question 4

bar

Answer 4

10^5 Pa; related unit of pressure (to pascal)

Question 5

Standard atmospheric pressure

Answer 5

typical pressure at sea level; pressure sufficient to support a column of mercury 760 mm high; in SI units, this pressure equals 1.01325 x 10^5 Pa

Question 6

atmosphere (atm)

Answer 6

non-SI unit used to express gas pressures

Question 7

torr

Answer 7

non-SI unit AKA mm Hg; named after Evangelista Torricelli (Galileo’s student) who did mercury/atmosphere pressure experiment

Question 8

Boyle’s law

Answer 8

the volume of a fixed quantity of gas maintained at constant temperature is inversely proportional to the pressure (V= constant x 1/p or PV = constant)

Question 9

Charles’s Law

Answer 9

the volume of a fixed amount of gas maintained at constant pressure is directly proportional to its absolute temperature

Question 10

Law of combining volumes

Answer 10

at a given pressure and temperature, the volume of gases that react with one another are in the ratios of small whole numbers; observed by Louis Gay-Lussac in 1808

Question 11

Avogadro’s hypothesis

Answer 11

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

Question 12

Avogadro’s law

Answer 12

the volume of a gas maintained at constant temperature and pressure is directly proportional to the number of moles of the gas (V = constant x n)

Question 13

Ideal-gas equation

Answer 13

PV = nRT

Question 14

ideal gas

Answer 14

hypothetical gas whose pressure, volume, and temperature behavior are described completely by the ideal-gas equation

Question 15

Gas constant

Answer 15

R in the ideal gas equation

Question 16

Standard temperature and pressure (STP)

Answer 16

conditions of 0 degrees Celsius & 1 atm; volume occupied by 1 mole of ideal gas at STP, 22.41 L is known as the molar volume of an ideal gas at STP

Question 17

Dalton’s law of partial pressures

Answer 17

the total pressure of a mixture of gases equals the sum of the pressures that each would exert if it were present alone

Question 18

partial pressure

Answer 18

pressure exerted by a particular component of a mixture of gases

Question 19

mole fraction

Answer 19

X; a dimensionless number that expresses the ratio of the number of moles of one component to the total number of moles in the mixture

Question 20

Kinetic-molecular theory

Answer 20

Rudolf Clasius’ theory of moving molecules (5 parts)

Question 21

root-mean-square (rms) speed

Answer 21

u; speed of a molecule possessing average kinetic energy

Question 22

effusion

Answer 22

escape of gas molecules through a tiny hole into an evacuated space

Question 23

diffusion

Answer 23

spread of one substance throughout a space or throughout a 2nd substance

Question 24

Graham’s law

Answer 24

law stating that the rate of effusion of a gas is inversely proportional to the square root of its molecular weight

Question 25

Mean free path

Answer 25

the average distance traveled by a molecule between collisions; varies with pressure

Question 26

van der Waals equation

Answer 26

an equation of state for nonideal gases that is based on adding corrections to the ideal-gas equation; the correction terms account for intermolecular forces of attraction and for the volumes occupied by the gas molecules themselves