WORKSHEET
JOULE QUESTIONS
1. The number of joules of heat energy released Base your answers to questions 13 and 14 on the fol-
when 20 grams of water are cooled from 20°C to lowing graph, which represents the uniform heating of
10°C is (1) 400 (2) 83.6 (3) 836 (4) 1672 a water sample at standard pressure, starling at a
temperature below 0°C.
2. Of the following kinds of matter, which is most
likely to be heterogeneous? (1) a compound (2) a
mixture (3) an element (4) a pure substance
3. When 167.2 joules of heat are added to 4 grams
of water at 10°C, the resulting temperature will be
(1) 8°C (2) 20°C (3) 40°C (4) 15°C
4. When the temperature of a system increases Joules added
by 20 Celsius degrees, the corresponding
temperature change on the Kelvin scale is 13. The number of joules required to vaporize the
(1) +20 (2) -20 (3) +293 (4) -253 entire sample of water at its boiling point is repre-
sented by the interval between (1) A and B
5. Any sample of a compound (1) can consist of one (2) E and F (3) C and D (4) D and E
element (2) is homogeneous (3) can have a varied
chemical composition (4) can be decomposed by 14. If 5 grams of water undergo a temperature
physical change change from C to D, the total energy absorbed is
(1) 418 joules (2) 500 joules (3) 1045 joules
6. Which Kelvin temperature is equivalent to (4) 2090 joules
20°C? (1) 20K (2) 253K (3) 273K (4) 293K.
15. How many joules of heat energy are released
7. A true solution is best described as a (1) hetero- when 50 grams of water are cooled from 70°C to
-geneous compound (2) homogeneous compound 60°C? (1) 418 joules (2) 209 joules (3) 2090 joules
(3) heterogeneous mixture (4) homogeneous mixture (4) 500 joules
8. Which formula represents a mixture? (1) NaCl(aq) 16. If 10.0 grams of water at 20°C absorb 418 joules
(2) NaCl(s) (3) H2O(l) (4) H2O(s) of heat, the temperature of the Water will be
increased by (1) 2C° (2) 5C° (3) 10C° (4) 30C°
9. Which change of phase is exothermic? (1) gas to
liquid (2) solid to liquid (3) solid to gas (4) liquid togas 17. The melting point of ice on the Kelvin scale
is (1) 0 K (2) 32 K (3) 80 K (4) 273 K
10. The normal boiling point of water is equal to
(1) 173 K (2) 213 K (3) 373 K (4) 473 K 18. A substance that has a definite shape and a
definite volume at STP Is (1) NaCl (aq) (2) Cl2 (g)
11. Which of the following best describes exothermic (3) CCI4 (l) (4) AlCl3(s)
chemical reactions? (1) They never release heat. (2)
They always release heat. (3) They never occur 19. What is the maximum mass of water that can be
spontaneously. (4) They always occur heated from 25°C to 30°C by the addition of 1254
spontaneously. joules of heat?
(1) 3,000grams (2) 300 grams
12. Which substance cannot be decomposed by a (3) 60 grams (4) 10 grams
chemical change? (1) mercury (II) oxide (2) potas-
sium chlorate (3) water (4) copper