Page 42 - FINAL DBS10012_HEAT TEMPERATURE 20102022 (2) (1)

EXERCISE 1.4

o
1. In preparing tea, 600 g of water at 90 C is poured into a 200 g pot at 20 C. What is the final temperature
o
o
of the water? Given, c pot = 0.84 kJ / kg C.
o
Answer: 85.6 C

5
2. Calculate the specific heat capacity of liquid y if 2.7 x 10 J amount of heat is needed to increase the
temperature of 5.3kg of liquid y from 21°C to 55 °C.

-1
Answer: 1498.34 J kg-1 °C

3. A metal spoon with mass 500g at 20°C temperature is heated till 100°C. Calculate the thermal

quantity absorbed by metal spoon. (Specific heat capacity for metal is 452J/kg °C).

Answer: 18080 J

4. A kettle holding full of water at 20°C needs 400kJ of energy to heat up until it reaches the temperature

of 100°C. If the specific heat capacity of water is 4200J/kg°C, find the mass of water.

Answer: 1.19kg

5. A 20 g cube of lead at temperature of 100 °C is put into water at temperature of 30 °C. After the two

materials are mix together the final temperature of the mixture is 35°C. Calculate the mass of the water.
-1
-1
Given specific heat capacity for lead = 1300 J kg °C .
Answer: 0.08kg

6. A cup of water A at 95 °C with mass of 150 g is poured into a bowl. Another cup of water B with at 30

°C is poured into the same bowl. If the mixture reaches a final temperature of 55 °C:

i) Calculate the heat released by water A

ii) Determine the mass of water B

-1
-1
(Specific heat capacity of water: 4200 J kg °C )
Answer: 25.2 kJ, 0.24 kg