Chp. 10: Gases

The number of moles of gas is denoted by:

n

Properties that define the state of a gas sample: n, P, V, and:

T (temperature)

P =

F/A

In P = F/A, what is F?

force

In P = F/A, what is A?

area

atmospheric pressure

weight of air per unit of area

pressure

the amount of force applied to an area

instrument for measuring pressure

barometer

The manometer is used to measure the difference in pressure between _______ pressure and that of a ________.

atmospheric; gas in a vessel

Standard atmospheric pressure atm

1

Standard atmospheric pressure torr/mmHg

760

Standard atmospheric pressure kPa

101.325

Boyle’s Law: At a fixed quantity of gas and constant temperature….

Volume is inversely proportional to pressure

Boyle’s Law Equation

P₁V₁=P₂V₂

PV is a constant because

V is directly proportional to 1/P

In gas law calculations, temperature is always measured in:

K

What happens to the pressure of a gas in a closed container if you double its volume while its temperature is held constant?

Decreases to half of its original value

Charles’s Law: At constant n and P…

V is directly proportionate to its absolute T

Charles’s Law Equation

V₁/T₁=V₂/T₂

Does the volume of a fixed quantity of gas decrease to half its original value when the temperature is lowered from 100 °C to 50 °C?

No because the temperature in kelvin (K) does not decrease by half

Gay-Lussac’s Law: At constant P and T…

the volume of gases that react with each other is in small whole numbers

Avogadro’s Law” At constant T and P…

volume is directly proportional to the number of moles of the gas

Avogadro’s Law Equation

V₁/n₁=V₂/n₂

STP one mole of ANY gas occupies:

22.4 L

Avogadro’s Law Equation reasoning

V = constant x n

Avogadro’s STP Relationships

1 atm = O C = 1 mol n = 22.4 L V

If 1.00 mol of an ideal gas at STP were confined to a cube,
what would be the length in cm of an edge of this cube?

(22,410)^1/3cm

Ideal Gas Equation

PV = nRT

Dalton’s Law of Partial Pressures

total pressure = the sum of the pressures of the individual gases

Kinetic-Molecular Theory: Gases consist of ________ of molecules that are in continuous, random motion.

large numbers

Kinetic-Molecular Theory: Gases consist of large numbers of molecules that are in _________ motion.

continuous, random

Kinetic-Molecular Theory: The combined volume of all the molecules of the gas is ________ relative to the total volume in which the gas is contained.

negligible

Kinetic-Molecular Theory: The combined volume of all the _________ is negligible relative to the total volume in which the gas is contained.

molecules of the gas

Kinetic-Molecular Theory: Attractive and repulsive forces between gas molecules are ________.

negligible

Kinetic-Molecular Theory: _________ between gas molecules
are negligible.

attractive and repulsive forces

Kinetic-Molecular Theory: Energy can be transferred between molecules during _______, but the average kinetic energy of the molecules does not change with time, as long as the temperature of the gas remains constant

collisions

Kinetic-Molecular Theory: Energy can be transferred between molecules during collisions, but the ______ kinetic energy of the molecules does not change with time, as long as the temperature of the gas remains constant

average

Kinetic-Molecular Theory: The _________ of the molecules is proportional to the absolute temperature.

average kinetic energy

Kinetic-Molecular Theory: The average kinetic energy of the molecules is proportional to the ____________.

absolute temperature

R in L - atm/mol - K

0.08206

R value in L - torr/mol - k

62.36