CHEMISTRY: Energy Unit REVIEW
Name____________________ Hr___
1. Know definitions and examples for each of the following terms:
potential energy
exothermic process/reaction
system
kinetic energy
endothermic process/reaction
surroundings
law of conservation of energy
heat
temperature
units for temperature, specific heat capacity, mass, and heat energy
calorimeter
2. State whether the following are exothermic or endothermic:
condensing water vapor
burning a candle
melting ice using a hot pack
reaction with a positive H
more energy needed to break chemical bonds of reactants than is released when bonds are formed
more energy released when bonds form than is needed to break chemical bonds of reactants
3. How much energy is required to raise the temperature of 40.0grams of water from 15.0C to
60.0C?
4. The specific heat of aluminum is 0.891 J/gC. How much energy is needed to raise the
temperature of a 300.0 gram block of aluminum from 20.2C to 75.5C?
5. If 1519 Joules of energy are added to a 645 gram piece of granite at 23.0C, what is the final
temperature of the granite? The specific heat of granite is 0.794 J/gC.
6. A piece of copper metal at 92.3 C is placed into 87.5ml of water at 12.4 C. The final
temperature of the metal and water is 19.9 C. The specific heat of copper is 0.3844 J/goC.
What is the mass of the copper?
7. The “Thermite Reaction” involves the single replacement reaction between iron(III) oxide and
aluminum metal. If the change in enthalpy (ΔH) of this reaction is -844.8kJ,
a) Write the energy term on the appropriate side of the reaction:
2 Al + Fe2O3  2 Fe + Al2O3
b) Calculate the amount of energy produced when 38.95grams of aluminum react with
excess iron(III) oxide.
8.
180kJ + N2 (g) + O2 (g)  2 NO (g)
What is the change in enthalpy of the reaction above? ____________________
Calculate the amount of thermal energy absorbed when 21.415g of nitrogen monoxide are
produced.
9. Draw a complete phase change diagram of water from -50C to 180C. Include all
temperatures and states of matter.
10. Calculate the heat energy released when 98.2 grams of water at 0.0C freezes to ice at 0.0 C.
11. How much energy is required for a steam boiler to heat 75.0 grams of water at 30.0C to steam
at 110.0C?
12. Calculate the total energy required to heat 17.0grams of ice at -35C to steam at 160C.
13. Answer the following questions using lab data from the specific heat lab, “Which Is Your
Metal?”
Mass of the unknown metal = 52.84 grams
Volume of the chilled water = 125.0mL
Initial temperature of unknown metal = 100.0C
Initial temperature of chilled water = 4.0C
Final temperature of water + metal = 12.0C
Known Specific Heat Capacities:
Sn: 0.2771 J/goC
Pb: 0.128 J/goC
Cu: 0.3844 J/goC
Zn: 0.3882 J/goC
Al: 0.8910 J/goC
a. Calculate the T for the metal and the T for the water.
b. Calculate the specific heat of the unknown, grey, shiny metal and identify the metal.