1.2 Changes Of State

Question 1

What is density?

Answer 1

Density is the measure of how much matter is within a given volume. P=M/V
Density quantifies how hard an object is. Usually, solid, liquid and gas in density. Water and ice is example of an exception. Eureka Can measures density.

Question 2

What is temperature?
Kelvin?

Answer 2

Temperature is the measure of the average kinetic energy of particles in a substance. Heat energy manifests itself in a substance as kinetic energy.
Kelvin = C + 273

Question 3

What is internal and potential energy?

Answer 3

Internal energy is the sum of kinetic and potential energy a substance’s particles have. Potential energy is dependant on the position of particles in a system.

Question 4

What is the difference between physical and chemical changes?

Answer 4

Physical changes have no new substance and same compounds before and after reaction. Easy to reverse by rearranging particles. Chemical changes have a new substance so different compounds before and after reaction. Chemical changes difficult to reverse.

Question 5

What is specific heat capacity?

Answer 5

The heat energy required to raise the temperature 1kg of a substance by 1 kelvin. Quantifies how easy or hard it is to change substance’s temperature.

E(j) = m(kg) * c(j/kg) * t(C or K)

Question 6

What is the key difference between latent heat and heat capacity?

Answer 6

If a temperature change occurs, kinetic energy has changed calculated with specific heat capacity.
If a state change occurs, internal energy has changed calculated with specific latent heat.

Question 7

What is specific latent heat?

Answer 7

Specific latent heat is heat energy transferred when 1kg of a substance changes from one state to another. Fusion applies to solid and liquid. Vaporisation applies to liquid and gas.

E(j) = m(kg) * L(j/kg)