Solid, liquids and gases

Question 1

Density equation

Answer 1

Density = mass/volume
ρ = m/v

Question 2

Investigating the Density of Regularly Shaped Objects

Answer 2

• Place the object on a digital balance and note down its mass
• Use either the ruler to measure the object’s dimensions (width, height, length, radius) – the apparatus will depend on the size of the object
• Repeat these measurements and take an average of these readings before calculating the density

Question 3

Investigating the Density of Irregularly Shaped Objects

Answer 3

• Place the object on a digital balance and note down its mass
• Fill the measuring cylinder with water
• Carefully lower the object into the cylinder
• Measure the volume of the displaced water in the measuring cylinder
• Repeat these measurements and take an average before calculating the density

Question 4

Investigating the Density of Liquids

Answer 4

• Place an empty measuring cylinder on a digital balance and note down the mass
• Fill the cylinder with the liquid and note down the volume
• Note down the new reading on the digital balance
• Repeat these measurements and take an average before calculating the density

Question 5

Pressure equation

Answer 5

Pressure = force/area
P = F/A

Question 6

Pressure difference equation

Answer 6

pressure difference = height × density × gravitational field strength
p = h × ρ × g

Question 7

Why do molecules in a gas have random motion and why do they exert a force and hence pressure on the walls of a container?

Answer 7

Gas Laws:
- Gas molecules have rapid and random motion.
- When they hit the walls of the container, they exert force

Question 8

Why there is an absolute zero of temperature which is -273°C

Answer 8

The particles have no thermal energy or kinetic energy, so they cannot exert a force.

Question 9

Describe the Kelvin scale of temperature and be able to convert between the Kelvin and Celsius scales

Answer 9

Zero Kelvin is equal to absolute zero (-273 °C)

Question 10

Why does temperature increase which results in an increase in the average speed of gas molecules?

Answer 10

As you increase the temperature of a gas, the kinetic energy of the gas particles increases and thus their average speed also increases

Question 11

Why does Kelvin temperature of a gas proportional to the average kinetic energy of its molecules?

Answer 11

The Kelvin temperature of a gas is proportional to the average kinetic energy of its molecules

Question 12

Qualitative relationship: pressure and volume at constant temperature

Answer 12

As you heat the gas, the kinetic energy of the particles increases, and thus so does their average speed. This means more collisions per second with the walls. This causes in the total pressure to rise

Question 13

Qualitative relative : pressure and Kelvin temperature at constant volume

Answer 13

If the same number of particles is placed in a container of smaller volume they will hit the walls of the container more often.
More collisions per second means that the particles are exerting a larger force on the wall over the same time, so pressure has increased

Question 14

Relationship between the pressure and volume of a fixed mass of gas at constant temperature equation

Answer 14

P1 V1=P2 V2

Question 15

Relationh