P1 - 1.6 Specific Heat Capacity

Question 1

What is meant by internal energy

Answer 1

The total energy stored by the particles making up a substance or system

Question 2

What 2 energy stores make up internal energy

Answer 2

Potential energy store
Kinetic energy store

Question 3

What are some potential energy stores relating to internal energy

Answer 3

Gravitational
Elastic

Question 4

True or False:
Potential energy stores are related to temperature

Answer 4

False

Question 5

True or False:
Potential energy stores are not really related to temperature

Answer 5

True

Question 6

What is an example of a kinetic energy store

Answer 6

The movement energy of particles

Question 7

Which energy store is important to internal energy

Answer 7

Kinetic energy stores

Question 8

How do we describe how energy is transferred when we heat an object

Answer 8

Kinetic energy is transferred to the surrounding via heat

Question 9

When you increase the kinetic energy store how does this affect the internal energy

Answer 9

Internal energy is increased

Question 10

What is temperature

Answer 10

A measure of the average internal energy of a substance

Question 11

What piece of equipment can we use to measure internal energy

Answer 11

Thermometer

Question 12

If we have a high internal energy how does this affect the thermometer

Answer 12

We will have a high temperature

Question 13

How much energy does 1kg of water need to increase by 1 degrees Celsius

Answer 13

4200J

Question 14

How much energy is required to increase 1kg of mercury by 1 degrees Celsius

Answer 14

139 degrees Celsius

Question 15

What is specific heat capacity

Answer 15

The amount of energy needed to raise the temperature of 1kg of a substance by 1 degrees Celsius

Can also be referred to as how much energy is released as a substance cools

Question 16

How much energy is given out when a 1kg water decreases by 1 degrees Celsius

Answer 16

4200J

Question 17

What is the calculation for specific heat capacity

Answer 17

Change in internal temperature = mass x specific heat capacity x temperature change

Question 18

What unit do we use for specific heat capacity

Answer 18

J/kg degrees Celsius

Question 19

Find the final temperature of 800g of water at an initial temp of 20 degrees Celsius after 20kJ of energy has been transferred to it the specific heat capacity of the water is 4200J/kg degrees Celsius

Answer 19

Change in internal energy = mass x specific heat capacity x mass x temperature change
change in internal energy / mass x specific heat capacity = temperature change
20,000/(0.8x4200) = 5.95 degrees Celsius
5.95+20= 25.95 degrees Celsius

Or 26.0 if we rounded it to 3 sf

Question 20

Why are our calculations technically not correct in real life when doing specific heat capacity calculations

Answer 20

Energy would be lost to the surroundings

Question 21

How can we prevent energy from being lost in a specific heat capacity practical

Answer 21

Using insulations such as a lid

Question 22

The particles in a s____ have kinetic energy because they are vibrating.

Answer 22

The particles in a solid have kinetic energy because they are vibrating.

Question 23

The particles in a l_____ or gas have kinetic energy because they move around.

Answer 23

The particles in a liquid or gas have kinetic energy because they move around.

Question 24

Temperature is a measure of the average kinetic energy of the p____ in a substance.

Answer 24

Temperature is a measure of the average kinetic energy of the particles in a substance.

Question 25

A kettle with 0.05 kg of water was heated from 25 °C, to the boiling temperature of 100 °C.

The specific heat capacity of water is 4,200 J/kg°C

How much heat energy is required?

Answer 25

100-25 = 75
0.05 x 4200 x 75
= 15750

Question 26

A beaker of water with a mass of 250g was heated until its internal energy increased by 21 kJ.

If the water’s original temperature was 24 °C, what is its final temperature?
(Specific heat capacity of water is 4,200 J/kg°C)

Answer 26

21kJ —> 21,000 J
M = 250g = 0.25kg
C= 4200J/kg degrees Celsius

21,000/ 0.25 x 4200 = 20 degrees Celsius

20+24 = 44 degrees Celsius

Question 27

To heat 20g of aluminium by 1*C requires 18 J of energy. To heat the same amount of gold only requires 2.6 J.

Which element must have higher specific heat capacity?
(You don’t have to do any calculations)

Answer 27

Aluminium

Question 28

A lump of gold with a mass of 20g was heated to 53 °C, and then allowed to cool down to 28 °C.

If gold’s specific heat capacity is 130 J/kg°C, how much internal energy did it lose in the cooling process?

Answer 28

ΔE = ?
m = 20 g = 0.02 kg
c = 130 J/kg°C
Δθ = 53 - 28 = 25 °C

ΔE = 0.02 x 130 x 25
= 65J