Properties of Matter Achieve

Question 1

Define specific heat capacity of a substance.

Answer 1

The amount of energy required to heat 1kg of a substance by 1 degree celcius.

Question 2

Where would you find values for the specific heat capacity of different substances?

Answer 2

The data sheet

Question 3

What are the units of specific heat capacity?

Answer 3

Jkg-1 C-1

Question 4

A substance with a high specific heat capacitance is heated for the time as a substance with a low specific heat capacity. Which will have the largest change in temperature – the high or the low?

Answer 4

The substance with low specific heat capacity.

Question 5

Write the equation to find the specific heat capacity of a substance.

Answer 5

E = cmΔT

Question 6

Calculate the energy required to heat 1 kg of water by 1°C.

Answer 6

E = cmΔT
4180x1x1
4180Jkg-1 C-1

Question 7

167200 J of energy is used to heat 4 kg of water. Calculate the temperature rise of the water.

Answer 7

E = cmΔT
167200=4180x4x?
167200/16720=?
10 degrees celcius

Question 8

3 kg of iron has an initial temperature of 18°C. It is heated by 30 kJ of energy. Calculate the final temperature of the iron.

Answer 8

Change of temperature= 22
T final= 22+18= 40

Question 9

What equipment is required to measure the specific heat capacity of a substance.?

Answer 9

Joule metre, scales, substance, heater, thermometer

Question 10

List the measurements needed to find the specific heat capacity of a substance.

Answer 10

• Energy the heater uses
• Mass of the substance
• Temperature of the substance before the heater is on
• The temperature after the heater is switched off

Question 11

State how to find the specific heat capacity of a substance using the following equipment. Wattmeter, timer, thermometer, substance, scales.

Answer 11

• Measure the mass of the substance.
• Measure the temperature of the substance before the heater is switched on.
• Time how long the heater is on for and the power it uses. Calculate the energy from the heater with E=Pt
• Measure the temperature when the heater is switched off and find the change in temperature.
  Insert into the equation. E = cmΔT

Question 12

A student measures the specific heat capacity of water to be lower than the value stated in the data sheet. Why might this be the case?

Answer 12

The heat could be lost to the surroundings.

Question 13

How can you prevent heat being lost to the surroundings of the specific heat capacity practical?

Answer 13

Insulate the material.

Question 14

Define the specific latent heat of a material.

Answer 14

The specific latent heat is the amount of energy required to change the state of a 1 kg substance.

Question 15

Where would you find the specific latent heat of different substances?

Answer 15

In the data sheet.

Question 16

What does vaporisation mean?

Answer 16

A substance changing from liquid to gas.

Question 17

What does fusion mean?

Answer 17

A substance changing from solid to liquid

Question 18

Two substances are heated – one with a large specific latent heat and one with a low specific latent heat. Which substance will take the least amount of energy to change state?

Answer 18

The substance with the small specific latent heat.

Question 19

What are the units of specific latent heat?

Answer 19

Jkg-1

Question 20

What is the equation to find the specific latent heat of a material?

Answer 20

E=ml

Question 21

What happens to the temperature of a substance when it is changing state?

Answer 21

Temperature stays constant.

Question 22

What kind of state change occurs when ice turns to water?

Answer 22

Fusion

Question 23

Calculate the energy required to melt 0.5 kg of ice.

Answer 23

E = ml

E = 0.5 × 3.34 × 105

E = 1.67 × 105 J

(l is found in the data sheet)

Question 24

It takes 40 kJ of energy to vaporise a mass of water. Calculate the mass of the water.

Answer 24

E = ml

40 × 103 = m × 22.6 × 105

m = 0.02 kg

Question 25

It takes 1025 kJ of energy to melt a 5 kg substance. From this information, what material was melted?

Answer 25

E = ml 1025000 = 5 × l l = 2.05 × 105 Jkg-1 l = copper

Question 26

Define the term ‘pressure’ in physics.

Answer 26

Pressure is the force per unit area.

Question 27

If the force is kept constant, what will happen to the pressure when the area is decreased?

Answer 27

Pressure increases.

Question 28

If the area is kept constant, what will happen to the pressure if the force is decreased.

Answer 28

The pressure will decrease.

Question 29

Force is...

Answer 29

Weight

Question 30

Using the kinetic model describe what happens to the pressure of a gas when the temperature is increased and the volume is kept constant.

Answer 30

When the **temperature increases** the **gas particles will again more kinetic energy**. This means they move with a **greater speed**. As a result they hit the **walls of the container more frequently** and with a **larger force**. Therefore, **because of P=F/A **and the area/volume is **kept constant increasing **the** force will increase the pressure**.

Question 31

Using the kinetic model describe what happens to the pressure of a gas when the volume is decreased and the temperature is kept constant.

Answer 31

When the **volume decreases** the gas particles will **hit the container walls more** **frequently**. This results in a **larger pressure**.

Question 32

Using the kinetic model describe what happens to the volume of a gas when the temperature is increased and the pressure is kept constant.

Answer 32

When the **temperature increases** the **gas particles will again more kinetic energy**. This means they move with a **greater speed**. As a result they hit the **walls of the container more frequently** and with a **larger force**. Therefore, because of **P=F/A** and the **pressure is kept constant increasing** the **force will increase the area** which **represents the volume of the container**.

Question 33

State absolute zero temperature in °C

Answer 33

-273 °C

Question 34

Calculate 10°C in Kelvin.

Answer 34

283 K

Question 35

Calculate the change in temperature in degrees Celsius between 278 K and 308 K.

Answer 35

30 °C

Question 36

What happens to the volume of an ideal gas if the pressure is increased and the temperature is kept constant?

Answer 36

Increases

Question 37

What happens to the volume of an ideal gas when the temperature is increased and the pressure is kept constant?

Answer 37

Increases

Question 38

What happens to the pressure of an ideal gas when the temperature is decreases and the volume is kept constant?

Answer 38

Decreases

Question 39

A syringe is connected to a pressure reader. How can this equipment be used to find the relationship between pressure and volume for an ideal gas?

Answer 39

Take measurements of the pressure at different volumes. Multiply P1 and V1 together then P2 and V2 and so on with all the data. This should give a constant and therefore: P1V1= constant P1V1=P2V2

Question 40

Describe an experiment to find the relationship between pressure and temperature when the volume of an ideal gas is kept constant.

Answer 40

Heat an ideal gas with a fixed volume. Take readings of the pressure and temperature of the ideal gas when the gas is being heated. Divide P1 by T1 (temperature in Kelvin) then P2 by T2 and so on with all the data. This should give a constant and therefore: P1/T1=P2/T2

Question 41

Describe an experiment to find the relationship between volume and temperature of an ideal gas when the pressure is kept constant.

Answer 41

Heat an ideal gas with a fixed pressure. Take readings of the volume and temperature of the ideal gas when the gas is being heated. Divide V1 by T1 (temperature in Kelvin) then V2 by T2 and so on with all the data. This should give a constant and therefore: V1/T1=V2/T2