Gases, Liquids, and Solids

Question 1

Pressure

Answer 1

Force/unit of area

Question 2

Gas properties

Answer 2

• Take the shape of the container
• No definite shape
• No definite volume
• Least dense phase of a substance

Question 3

Standard pressure

Answer 3

1 atmosphere, 101.3 kPa, 760 torr, 760 mm Hg

Question 4

Boyle’s Gas Law (movable piston)

Answer 4

P1V1 = P2V2

• Indirect relationship
• As pressure increases, volume decreases
• As pressure decreases, volume increases

Question 5

Charles’ Gas Law

Answer 5

V1/T1 = V2/T2

• Direct relationship
• As temperature increases, volume increases
• As temperature decreases, volume decreases

Question 6

What is important to remember about Charles’ law?

Answer 6

Temperature must be in Kelvin

Question 7

Combined gas law

Answer 7

P1V1/T1 = P2V2/T2

Question 8

Diffusion

Answer 8

The movement of gas particles from a region of high concentration to low concentration

Question 9

Graham’s law of diffusion

Answer 9

v1/v2 = square root of m2/m1

v = velocity
m = mass

Question 10

Which gas diffuses the fastest? Slowest? Why?

a) CO2 b) He c) N2 d) SO2

Answer 10

He diffuses the fastest because it has the smallest mass

SO2 diffuses the slowest because it has the largest mass

Question 11

Dalton’s law of partial pressure

Answer 11

The total pressure in a room is equal to the sum of the partial pressures of the gases

Question 12

Partial pressure setup for air

Answer 12

P total pressure of air = P N2 + P O2 + P Ar

Question 13

How do you calculate partial pressure?

Answer 13

Moles of one individual gas x total pressure/sum of total moles

Question 14

Characteristics of an ideal gas

Answer 14

• Gas particles are in constant, random, straight line motion
• Gases collide with each other and the walls of the container
• Gas particles are separate by great distances and have a negligible volume
• Gas particles do not attract each other

Question 15

Which 2 gases behave most like an ideal gas?

Answer 15

Hydrogen and helium because they are the smallest elements with the smallest densities and radii. Helium is also inert.

Question 16

Under which conditions does a gas become an ideal gas?

Answer 16

High temperatures and low pressure

Question 17

Liquid properties

Answer 17

• More dense than gas phase, but less dense than solid phase
• Takes shape of container
• Definite volume

Question 18

Vapor pressure

Answer 18

In a closed system, the vapor formed from the evaporation of a liquid or the sublimation of a solid that exerts a pressure on the walls of the container

Question 19

What happens to vapor pressure as temperature increase?

Answer 19

As temperature increases, vapor pressure increase

Question 20

If particles have a high vapor pressure and escape easily to the gas phase, they have…

Answer 20

Weak bonds or intermolecular forces

Question 21

Intermolecular forces

Answer 21

Forces between molecules

Question 22

If particles have a low vapor pressure, they have…

Answer 22

Strong intermolecular forces

Question 23

Boiling point

Answer 23

The temperature at which the vapor pressure of the liquid or solid is equals to the external air pressure around it

Question 24

Normal boiling point

Answer 24

The temperature at which vapor pressure equals standard pressure

Question 25

Solid properties

Answer 25

• Definite shape and definite volume
• Most condense phase

Question 26

What is the only exception to the density rules of solids, liquids, and gases?

Answer 26

Water in the solid ice phase is less dense than water in the liquid water phase (ice floats)

Question 27

Crystal/crystalline solids

Answer 27

A regular, repeating, geometric pattern

Question 28

Examples of crystals

Answer 28

NaCl, dry ice or CO2(s), Cdiamond, Cu)

Question 29

Amorphous solids

Answer 29

Lacks structure and doesn’t have a regular, repeating, geometric pattern

Question 30

Examples of amorphous solids

Answer 30

Glass, plastic, silicon, clay

Question 31

Do solids have kinetic energy?

Answer 31

Yes, solids have kinetic energy even though their relative position doesn’t change