  Unit 4 Quiz--Heat Calculations

Multiple Choice (Choose the best answer.)

For problems 1 - 3 you will need to use the relationship, Heat = Specific Heat x Mass x T.

1. How much energy (in calories and in Joules) will it take to raise the temperature of 75.0 g of water from 20.0 to 55.0 oC? ( Specific Heat = 1 cal / ( g oC ) and 4.184 J / ( g oC ) )

2630 cal and 630. J

2630 cal and 1.1 x 10 4 J

1.1 x 10 4 cal and 2630 J

630. cal and 2630 J

None of these are correct.

2. 350 J are released as ice ( Specific Heat = 2.1 J / (g oC) ) cools from - 5.0 oC to -32 oC. What is the mass of ice?

0.16 g

6.2 g

4.5 x 10 3 g

2.0 x 10 4 g

None of these are correct.

3. A 63.0 g piece of aluminum (Specific Heat = 0.215 cal / (g oC) ) at 25.0 oC is warmed by the addition of 325 calories of energy. Find the final tempearture of the aluminum.

49.0 oC

240. oC

26.1 oC

1.11 oC

None of these are correct.

For problems 4 - 7 you will need to use the heat of fusion ( Hfus ) or the heat of vaporization ( Hvap ).

4. How much energy would be required to melt 15.0 g of ice at 0 oC? Hfus = 6.01 KJ/mol

90.2 KJ

7.21 KJ

5.01 KJ

0.200 KJ

None of these are correct.

5. How many moles of ice at 0 oC could be melted with the addition of 750 KJ of energy? Hfus = 6.01 KJ/mol

8.0 x 10 -3

4.4 x 10 -4

2200 mol

120 mol

None of these are correct.

6. How much energy would it take to boil 36.0 g of water at 100 oC? Hvap = 40.7 KJ/mol

81.4 KJ

1470 KJ

1.13 KJ

0.0123 KJ

None of these are correct.

7. How many grams of steam could be condensed at 100 o C with the removal of 307 KJ of energy? Hvap = 40.7 KJ/mol

7.37 x 10 -3 g

7.54 g

17.1 g

136 g

None of these are correct.

For problems 8 - 10 you will need to use the heat of fusion ( Hfus ) , specific heat, or the heat of vaporization ( Hvap ) in combinations with one another. Use the values for Hfus, specific heat, or Hvap for water listed earlier in the quiz.

8. How much energy would it take to melt 30.0 g of ice at 0 oC and warm the resulting liquid to 35.0 oC?

4.39 KJ

10.0 KJ

14.4 KJ

4400 KJ

None of these are correct.

9. How much energy would it take to warm 30.0 g of water at 35 oC to the boiling point and boil all the liquid away?

8.20 KJ

76 KJ

8200 KJ

8268 KJ

None of these are correct.

10. How much energy would be reqired to melt 10.0 g of ice at 0 oC, warm the resulting liquid to 100 oC, and change it to steam at 100 oC?

3.34 KJ

4.18 KJ

22.6 KJ

4210 KJ

None of these are correct. Back to Unit 4 Main Page Back to Chemweb Main Page