Spring 1999

MWF 11:30

**Instructor**: Dr. Amit Chakrabarti, CW 213, Tel: 532-1625.

# Home Work 6

CONCEPTUAL QUESTIONS:

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These assignments are from the text book:

CHAPTER 12 EXERCISES 1,3,6 (PAGE 230)

CHAPTER 14 REVIEW QUESTIONS 7,11,12,13,15,16

(PAGE 267)

EXERCISES 8,11,13,15,20 (PAGE 267-268)

CHAPTER 15 REVIEW QUESTIONS 4,6 (PAGE 284)

EXERCISES 5,7,13,18,34,39,42 (PAGE 285-287)

CHAPTER 16 REVIEW QUESTIONS 32,33,34,38,39,41

(PAGE 300-301)

EXERCISES 19,20,30 (PAGE 302)

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PROBLEMS :

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1. How much heat is required to raise the temperature of 0.5 kg water
from 20 degree Celsius to 30 degree Celsius ? The specific heat of
water is 4200 J/kgC.

2. 0.1 kg of water at 70 degree Celsius is mixed with an equal amount of
cold water at 30 degree Celsius in a completely insulated container. The
final temperature of the water is 50 degree Celsius. The specific heat of
water is 4200 J/kgC.

(a) How much heat is lost by the hot water ?

(b) How much heat is gained by the cold water ?

3. An iron bar has a mass of 2 kg. If it takes 3680 J to raise its
temperature by 4 degree Celsius, what is the specific heat of iron?

4. How much heat would it take to melt a 5 kg block of ice at 0 degree
Celsius ? The latent heat of fusion of ice is 320 kJ/kg.

5. How much heat would be released when 0.1 kg of steam at 100 degree Celsius is
converted to water at 100 degree Celsius ? The latent heat of vaporization
of steam is 2260 kJ/kg.

6. How much heat is required to convert 0.4 kg of ice at -5 degree
Celsius to water at +5 degree Celsius ? The specific heat of ice is
2100 J/kgC and the specific heat of water is 4200 J/kgC.
The latent heat of fusion of ice is 320 kJ/kg.

(Hint: You have to do this problem in three steps. First, find how much
heat is required to increase the temperature of ice from -5 degree
Celsius to 0 degree Celsius (the ice remains as ice upto this point
and you will need the specific heat of ice for this calculation), next
find how much heat is needed to change the ice into water at 0 degree
Celsius( you will need to use the latent heat of fusion of ice for this
calculation), now find the amount of heat needed to increase the
temperature of water from 0 degree Celsius to 5 degree Celsius (you
will need the specific heat of water for this calculation).