Page 22 - FINAL DBS10012_HEAT TEMPERATURE 20102022 (2) (1)

EXERCISE 1.2

1. Zulkifli is heating up water with a mass of m kg and later on is been cooled from 98 °C to 45 °C.
Calculate the mass of the water if the amount of lost heat is 9.6 kJ.

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(Specific heat capacity of water = 4200 J kg °C )
Answer: 0.043 kg

2. A bottle containing 1.5 kg of water at 34°C is put into a refrigerator. What is the temperature of
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the water after 1.575 x 10 J of heat has been removed from the water? (Specific heat capacity of
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water = 4200 J kg °C ).
Answer: 9 °C

3. A piece of steel plate with a mass of 6000 g is heated from 20°C to 55°C, if the given specific heat

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capacity is 500 J kg °C , calculate the amount of heat of the steel plate.
Answer: 105,000 J

4. An electric kettle has a power rating of 2.4 kW. How long does it take the kettle to heat up 4.5 kg

of tap water from 28 °C to 100 °C? What assumption must you make to arrive at the answer?
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(Specific heat capacity of water = 4200 J kg °C )
Answer: 567 s

5. Calculate the final temperature of a copper block when the mass of the block is 3 kg at 35 °C and

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received heat at 60.1kJ. Given specific heat capacity for copper = 390 J kg °C
Answer: 86.37 °C

6. Calculate the amount of heat required to raise the temperature of 5 kg of iron from 25 °C to 55 °C.
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(Specific heat capacity of iron=500 Jkg °C ).
Answer: 75,000 Joule @ 75kJ

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