5.3 The Gas Laws and Their Experiment Foundations

Question 1

Ideal gas law

Answer 1

quantitatively describes the behavior of an ideal gas

Question 2

Ideal gas

Answer 2

one that exhibits linear relationships among volume, pressure, temperature, and amount

Question 3

Corresponding P and V values

Answer 3

V is INVERSELY PROPORTIONAL to P
V is DIRECTLY PROPORTIONAL to 1/P
Plot of V and 1/P is LINEAR

Question 4

Boyle’s law

Answer 4

V ∝ 1/P [T and n are fixed]
so, V↑ P↓, and V↓ P↑

At constant temperature, the volume occupied by a fixed amount of gas is inversely proportional to the applied (external pressure):

Question 5

Charles’s law

Answer 5

V ∝ T [P and n are fixed]
so, V↑ T↑, and V↓ T↓

At constant pressure, the volume occupied by a fixed amount of gas is directly proportional to its absolute (kelvin) temperature:

Question 6

Pressure - Temperature Relationship

Answer 6

P ∝ T [V and n are fixed]
so, P↑ T↑, and P↓ T↓

At constant volume, the pressure exerted by a fixed amount of gas is directly proportional to the absolute temperature

Question 7

Combined Gas Law

Answer 7

V ∝ (T/P)

Question 8

Avogadro’s Law

Answer 8

at a fixed temperature and pressure, equal volume of any ideal gas contains equal numbers of particles (or moles):

V ∝ n

Question 9

Standard temperature and pressure (STP)

Answer 9

set of standard conditions:

STP: 0°C (273.15 K) and 1 atm (760 torr)

Question 10

Standard molar volume

Answer 10

22.4141 L or 22.4L

Question 11

Ideal Gas Law

Answer 11

PV = nRT

Question 12

Solving Gas Problems: a change in one of the four variables cause a change in another, while the two other variables remain constant

Answer 12

• units must be consistent
• T is always in K, R is NOT involved
• ideal gas law reduces to one of the two individual gas laws; solve for the new value of the affected variable

Question 13

Solving Gas Problems: one variable unknown, but the other three are known and no change occurs

Answer 13

• apply ideal gas law directly to find the unknown
• all units must conform to those in R
• summarize the changing gas variables and those held constant
• convert units if necessary
• rearrange the ideal gas law to obtain the needed relationship of variables, and solve for the unknown