Name: _____________________________
Date: _____________
Assignment #1
Specific Heat Capacity
Use ∆E = mc∆T to solve the following problems.
1. How much heat is needed to raise the temperature of 90.0 kg of water from 18˚C to 80°C?
∆E = mc∆T
∆E = (90.0 kg)(4200 J/kg/˚C)(80-18 ˚C)
∆E = 23 436 000 J = 23.4 MJ
2. If 1.0 MJ (megajoule) of heat is transferred to 10.0 kg of water initially at 15˚C, what will its
final temperature be?
23.8˚C + 15˚C = 38.8˚C
3. If 12.0 kg of water cools from 100°C down to room temperature (20°C), how much heat will
it release to the environment?
∆E = mc∆T
∆E = (12.0 kg)(4200 J/kg/˚C)(20-100 ˚C)
∆E = -4 032 000 J = -4.032 MJ (negatives indicates energy given
off)
4. Why is water such a desirable material to use as a coolant in a car engine? Water has a very
high heat capacity so it can hold a lot of heat, helping to cool down an engine more
quickly.
5. If it takes 1200 J to raise the temperature of 0.500 kg of brass from 20.0˚C to 26.2°C, what is
the specific heat capacity of brass?
∆E = mc∆T
c = ∆E /(m∆T)
c = (1200 J)/[(0.500kg)(26.2-20.0 ˚C)]
c = 387 J/kg/˚C
6. How much heat would be needed to warm 1.6 kg of ice from -15°C up to its melting point of
0.0°C?
∆E = mc∆T
∆E = (1.6 kg)(2100 J/kg/˚C)(0.0- -15 ˚C)
∆E = 50 400 J = 50.4 kJ
7. A 5.0 kg block of lead at 250°C cools down to 20°C. How much heat does it give off in
doing so?
∆E = mc∆T
∆E = (5.0 kg)(130 J/kg/˚C)(20-250 ˚C)
∆E = -149 500 J = -149.5 kJ (negative implies energy given off)
Table of Specific Heat Capacities
SUBSTANCE
(J/kg/˚C)
SUBSTANCE
(J/kg/˚C)
water
4200
steam
2100
methyl alcohol
2400
aluminum
920
ethylene glycol (antifreeze)
2200
glass
840
ice
2100
iron
450
kerosene
2100
copper
430
lead
130