P1.2

Question 1

what are the 5 main ways that a substance can change state?

Answer 1

melt
freeze
evaporate
condense
sublimate

Question 2

what is sublimation

Answer 2

when a substance transitions from a solid straight to a gas without transitioning into a liquid in between

Question 3

what is always conserved when a substance changes state

Answer 3

mass

Question 4

how does a change of state differ from a chemical change

Answer 4

in a change of state, the material can return to having its previous properties if the change is reversed

Question 5

what two things can heating a substance do?

Answer 5

raise its temperature
change the state of the substance

Question 6

define specific heat capacity

Answer 6

the amount of energy needed to increase the temperature of 1kg of a substance by 1 degree celcius

Question 7

what can be said about a material if it has a higher specific heat capacity?

Answer 7

for a constant mass, the material will need more energy to achieve a given temperature change.

Question 8

define specific latent heat

Answer 8

the amount of energy needed to change the state of 1kg of a substance with no change in tempertature

Question 9

state the equation for the energy required to change state. give appropriate units

Answer 9

E = mL
energy to change state = mass x specific latent heat
energy (J), mass(Kg), specific latent heat (J/kg)

Question 10

what is the internal energy of a substance

Answer 10

the energy stored by the particles
the sum of the total kinetic and potential energies that make up the system