Molecules and matter

Question 1

What is density’s formula

Answer 1

density (kg/m³) = mass (kg) / volume (m³)

Question 2

What is the difference between evaporation and boiling?

Answer 2

evaporation occurs at lower temperatures below a substance’s boiling point at its surface, whereas boiling is the whole substance rising above its boiling point.

Question 3

What is the conversion between cm³ and ml³

Answer 3

they are the same

Question 4

What is internal energy?

Answer 4

the sum of a substance’s potential and kinetic energy

Question 5

What is kinetic energy?

Answer 5

how fast particles move

Question 6

What is potential energy

Answer 6

how the structure of particles change (become more separate / randomised )

Question 7

What are the two ways a substance’s internal energy can change?

Answer 7

-when the thermal energy of an object changes but its state stays the same.
if a liquid gets heated but not to the point where is boils, its particles spread further apart but not into a gas, the particles gain kinetic energy

-when the material’s state changes but its temperature stays the same.
if a substance changes state, bonds break as they move further apart, gaining potential energy

Question 8

What is specific heat capacity?

Answer 8

how much energy is required to heat a 1kg object by 1ºC without changing state.

Question 9

What is the formula to calculate energy required to heat a 1kg object by 1ºC:

Answer 9

energy (J) = mass (kg) x SHC (kg/mºC) x temperature change (ºC)

Question 10

What does an object’s SHC depend on?

Answer 10

-its mass
-its material
-the energy supplied to it