Chapter 6 - Molecules and Matter

Question 1

What is the formula needed to calculate density?

Answer 1

mass, m (kg)
___________
volume, V (m3)

Question 2

RQP = Describe an experiment to find a density of an object.

Answer 2

1. Use a measuring cylinder to measure the volume of the liquid.
2. Measure the mass of an empty beaker using a balance.
3. Pour liquid from the measuring cylinder into the beaker
4. Measure the total mass of the beaker and the liquid
5. Calculate the mass of the liquid by subtracting the total mass of the beaker + liquid and the mass of the empty beaker.
6. Calculate the density of the liquid using the equation above.

Question 3

Explain the arrangement of particles in a solid, liquid and gas.

Answer 3

• The particles in a solid are in fixed positions held together. They subtly vibrate on the spot. Their volume is fixed, they have high density, and they do not flow. It’s shape is fixed.
• The particles in a liquid move in random directions but are held together. Liquids flow, have a fixed volume and a high density. It can fit the shape of a container.
• The particles in a gas move about randomly and are far apart. Gases flow, fills the container they are in, it’s volume can be changed, and it has a low density.

Question 4

What is the change of state called when:

• A solid turns into a liquid
• A gas turns into a liquid
• A solid turns into a gas
• A gas turns into a solid

Answer 4

• Melting
• Condensation
• Sublimation
• Deposition

Question 5

What is a substance’s internal energy?

Answer 5

• The energy stored by the particles of a substance.

Question 6

What happens to the kinetic energy of a substance when the temperature rises?

Answer 6

• The kinetic energy of the particles of the substance increases.

Question 7

An ice cube has melted a changed state into a solid. State the change of the potential energy of the particles.

Answer 7

• The potential energy of the particles have increased.

Question 8

Latent heat is……

Answer 8

• the energy needed to change the state of a substance without changing it’s temperature.

Question 9

What is the Specific Latent Heat of Fusion?

Answer 9

• The energy needed to melt 1kg of a substance without temperature change.

Question 10

Water vapour is the gas produced from boiling a kettle. State what the Specific Latent Heat of Vaporisation is.

Answer 10

• The energy needed to boil 1kg of a substance without temperature change.

Question 11

What is the formula needed to calculate the Specific Latent Heat (of Fusion/Vaporisation)?

Answer 11

E = mL(f/v)

E - Energy (J)
m - Mass (m)
L (f/v) - Latent Heat of (Fusion/ Vaporisation)

Question 12

Calculate the energy transferred to the surroundings as 0.60 kg of stearic acid changed state from liquid to solid.

The specific latent heat of fusion of stearic acid is 199 000 J/kg.

Answer 12

1. E = mLf
2. E = 0.6 x 199,000
3. E = 119,400 J

Question 13

How much energy is needed to boil 500 grams (g) of water from 0°C?

   The specific latent heat of vaporisation of water is 2,260 J/kg.

Answer 13

1. E = mLv
2. E = 0.5 x 2,260
3. E = 1,130 J

Question 14

What is the equation for Boyle’s Law?

Answer 14

pV = constant

P - Pressure (Pa)
V - Volume (m3)

Question 15

When the pressure of a gas increases, the volume…..

Answer 15

• decreases

Question 16

What happens when a volume of a gas decreases in terms of molecules?

Answer 16

• The number of molecular impacts on the surfaces increase.