Specific heat capacity

Question 1

Define SHC

Answer 1

amount of energy required to raise the temperature of 1 kg of a substance by 1 degree celsius

Question 2

What is the formula for SHC ?

Answer 2

change in thermal energy = mass * shc * temp change

Question 3

What is the SHC of water ?

Answer 3

4200 J Kg/C

Question 4

What are the units for mass, temp change, thermal energy and SHC ?

Answer 4

mass = kg
temp change = C
thermal energy = J
SHC = J / Kg C

Question 5

SHC practical

Answer 5

• place beaker on mass balance, set to 0
• add liquid to beaker, record mass
• place thermometer and immersion heater in liquid
• record start temp of liquid
• wrap insulating foam around beaker
• connect joulemeter to heater
• leave for 30 min, record number of Joules that passed into heater
• record final temp, calculate SHC

Question 6

How hot does a 3.5 kg brick get if it’s heated from 20°C by 20,000 J (20 kJ)?

Answer 6

26.8 degrees

Question 7

Calculate the SHC of a 3kg piece of metal which experiences a temperature rise of 25 degrees when heat is supplied to it at a rate of 60 Watts for 10 minutes, if a total of 3000J escapes to the surroundings.

Answer 7

Step 1: E = Pt
- 60 * 10 * 60 = 36, 000 J
Step 2: subtract dissipated energy
- 36,000 J - 3000 J = 33,000 J
Step 3: plug values into formula
- E = m * c * temp change
33,000 = 3 * 25 * c
33,000 / 75 = 440 J/kg C