Chapter 11/12

Question 1

What are the three states of matter?

Answer 1

Solid - the largest attractive forces in it; definite shape and volume; incompressible

Liquid - takes the shape of container; definite volume; flows; somewhat compressible

Gas - takes the shape and volume of container; flows; highly compressible

Question 2

What is the Kinetic Molecular Theory (KMT)?

Answer 2

The idea that all substances are composed of entities that are in constant, random motion

Question 3

What is kinetic energy?

Answer 3

The energy of an entity due to its motion (the higher the temperature, the more movement, the higher kinetic energy)

Question 4

What are the 3 types of motion that molecules can exhibit?

Answer 4

Translational - the movement of entities through space along a linear path (in gases and liquids)

Rotational - the spinning of an entity in place (in gases and liquids)

Vibrational - the back and forth vibration of entities (in gases, liquids and solids)

Question 5

What limits motion?

Answer 5

Strong attraction

Why solids don’t move as much as liquids and gases

Question 6

What results when a substance is warmed for a long period of time?

Answer 6

As a substance is warmed, the kinetic energy increases as well as the temp

If it continues to be warmed, the kinetic energy absorbed helps the molecules to overcome the attractive forces between the entities, which results in a change of state

Question 7

What is pressure?

Answer 7

The force per unit area. SI (standard) unit for pressure is Pa (kPa)

It is a physical property of gas

Question 8

What causes pressure?

Answer 8

Pressure is due to collisions of gas particles. Pressure increases because the speed of the particles increases (more collisions per second)

Question 9

What is STP and STAP?

Answer 9

Standard temperature and pressure - 101.325 kPa and 273 K

Standard ambient temperature and pressure - 100 kPa and 25 C (298 K)

Question 10

What is atmospheric pressure? How was it first determined?

Answer 10

The force per unit area by air on all objects

Determined via an inverted tube of mercury

Question 11

How does volume vary with temperature?

Answer 11

Gases shrink if cooled

Gases expand if heated

Question 12

Why is 20 kg twice as heavy as 10 kg but 20 C isn’t twice as hot as 10 C?

Answer 12

Weight has a minimum value of zero

However the smallest temperature is not 0 degrees Celsius

Question 13

What is the Kelvin temperature scale?

Answer 13

If a volume vs temperature graph is plotted for gases, when volume is zero temperature is -273 C

-273 C is known as absolute zero, or 0 K

Therefor 0 C is 273 K

K = C + 273

Question 14

What is Charles’ law?

Answer 14

There is a direct relationship between volume and temperature

As the volume increases, the temp increases proportionally as long as the pressure and amount of gas remains constant

V1/T1 = V2/T2

MUST BE IN KELVINS

Question 15

What is Boyle’s law?

Answer 15

States that when gases are under pressure, it take up less space

The higher the pressure, the lower the volume

States pressure is inversely proportional to volume at constant temperature

P1V1 = P2V2

Question 16

What is Gay-Lussac’s law?

Answer 16

Pressure and absolute temperature (K) of a gas are directly related at a constant mass and volume

P1/T1 = P2T2

Question 17

What is the combined gas law?

Answer 17

P1V1/T1 = P2V2/T2

Question 18

What is Avogadro’s law?

Answer 18

The volume of a gas is directly related to the number of moles of gas when T and P are constant

V1/N1 = V2/N2

Question 19

What is molar volume?

Answer 19

At standard temperature and pressures (STOP or STAP), 1 mole of gas occupies a volume of 22.4 L at STP and 24.8 L at STAP

A conversion factor to convert moles to liters

Question 20

What are ideal gases?

Answer 20

Gases that exhibit certain theoretical properties (obeys all gas laws under all conditions, doesn’t condense into a liquid when cooled, etc.)

A completely ideal gas does not technically exist but we assume gases are ideal to simplify our calculations

Question 21

What is the ideal gas law?

Answer 21

PV = nRT

P is pressure in kPa
V is volume in liters
T is temp in K
n is moles
R is 8.31 (a constant)