States Of Matter

Question 1

What are the phases/states of matter

Answer 1

Solid, liquid, gaseous state

Question 2

What are the differences between the 3 states of matter

Answer 2

Solid - strong cohesive forces, definite shape & volume, particles only vibrate
Liquid - less strong cohesive forces, definite volume, takes shape of container, particles slide over each other
Gases - negligible cohesive forces, indefinite volume & shape, particles move freely and randomly

Question 3

What is sublimation

Answer 3

It is the change of state of a substance from solid to gas directly

Question 4

State the names given to the conversion of each state of matter to another

Answer 4

Solid - liquid: melting/fusion
Solid - gas: sublimation
Liquid - solid: freezing
Liquid - gas: vapourization
Gas - solid: deposition
Gas - liquid: condensation

Question 5

What is the temperature at which the saturated vapour pressure is equal to the atmospheric pressure called

Answer 5

Boiling point

Question 6

When is the vapour pressure of a liquid saturated?

Answer 6

When the number of loquid molecules evaporating/vapourizing is equal to the number of vapour molecules condensing

Question 7

Describe the change of atmospheric pressure with altitude

Answer 7

Atmospheric pressure reduces with increasing altitude and vice versa

Question 8

Describe the change of boiling points with atmospheric pressure

Answer 8

As atmospheric pressure increases, the boiling point rises and vice versa

Question 9

What is latent heat

Answer 9

It is the heat absorbed or released by a substance during a phase change without a change in temperature

Question 10

During which phase changes is heat absorbed/gained

Answer 10

Melting, vapourization/boiling, sublimation

Question 11

During which phase changes is heat released

Answer 11

Freezing, condensation, deposition

Question 12

What are the phenomena that support kinetic theory of matter

Answer 12

Diffusion, osmosis, brownian motion

Question 13

What are the assumptions of kinetic theory

Answer 13

• Gas particles are in constant rand motion in a straight line
• Their collisions are perfectly elastic
• Their collisions with the walls of the container results in pressure
• The volume fo gases are negligible when compared to the volume occupied
• The cohesive forces between gas particles are negligible
• Tbe temperature is a measure of the average kinetic energy of the particles

Question 14

State Charles’s law

Answer 14

At constant pressure, the volume of a given mass of gas is directly proportional to the temperature

Question 15

State dalton’s law of partial pressure

Answer 15

(1802)It states that when there is a mixture of gases which do not react chemically together, the total pressure of the system is the sum of the partial pressures of the individual elements

Question 16

State Graham’s law of diffusion

Answer 16

(1833) It states that the rate of diffusion of a gas is inversely proportional to the square root of its density

Question 17

What is the critical temperature of a gas

Answer 17

It is the temperature above which a gas cannot be liquefied by pressure

Question 18

What is the critical pressure of a gas

Answer 18

It is the pressure at which the critical temperature is just enough to liquify the gas

Question 19

State gay-lussac’s law of combining volumes

Answer 19

It states that when gases react, they do so in volumes which are simple ratios to one another and to the volumes of their products if gaseous provided that the temperature and pressure are kept constant

Question 20

Mention some applications of Graham’s law

Answer 20

• it’s used to separate mixed gases(atmolysis)
• It’s used to determine density of gases

Question 21

State avogadro’s hypothesis

Answer 21

It sates that equal volume of all the gases at the same temperature and pressure contain the same number of molecules

Question 22

When do avogadro and Gay-lussac laws hold

Answer 22

At low pressures

Question 23

What is the formula for calculating root mean square velocity

Answer 23

(3RT/m(in kg/mol))½

Question 24

The velocities of gases are inversely proportional to the square root of their vapour densities.
True or false

Answer 24

True

Question 25

What is the velocity of molecules of a gas given in terms of R, T and momentum(m)

Answer 25

c =(3RT/m)^½

Question 26

At what conditions are gas laws obeyed more by gases

Answer 26

High temperatures and low pressures

Question 27

What are the causes of the deviation from avogadro’s hypothesis and gay lussac’s law

Answer 27

The mutual attraction of molecules
The actual volume of the gas molecules

Question 28

Do ideal gases condense

Answer 28

Gas laws do not account for condensation and believes that at 0K the volume of gases should be zero, but all gases condense before that temp.