Name_____________________
1. How much heat is needed to raise the temp. of 350 g of water from 25.0 °C to 95.0 °C ?
2. 37,500 Joules of energy is added to 254 g of an unknown metal. If the temperature of the metal goes from 22.0°C to 97.0°C , what is the specific heat capacity of the metal?
3. If 85,300 Joules of energy is added to an unknown amount of copper at 15.0°C the temperature goes to 78.0°C. Calculate the mass of the copper metal.
4. If 33,600 joules of energy is added to 287.5 g of zinc at 25.0°C calculate the final temperature of the zinc.
5. 358g of an unknown metal at 100.0°C is placed into 305 g of water at 23.5°C. If the temperature goes to 25.0°C, what is the specific heat of the metal?
6. An unknown amount of aluminum at 87.0°C is placed into 250 g of water at 22.0°C. If the final temperature of the water and aluminum is 26.5°C, what is the mass of the aluminum?
7. If 85.0 g of magnesium at 95.0°C if placed into 150 g of water at 23.0°C what is the final temperature of the mixture?
_____8. Identify the activation energy in the above diagram
_____ 9. Identify the enthallpy change in the above diagram.
_____ 10. The reaction in the above diagram is ___________.
(a) endothermic (b) exothermic (c) isothermic
Given the following heats of formation KJ/mole
H2O = -242 Ca(OH)2 = -987 C2H6 = -84.7
CO2 = -393.5 CO= -26.4 NH3 = -46.1 NO2 = +33.2
_____11. Determine the enthalpy for the following reaction
Ca(OH)2 + H2 ---> 2H2O + Ca
_____12. The above reaction is an example of an ___________ reaction.
13.Rewrite the reaction in question #12 including the energy term.
_____ 14. If 150.0 g of Ca(OH)2is reacted with excess H2, how much energy will be needed?
_____15. If 35,600 joules of energy is consumed in the above reaction, how many grams of Calcium will be produced?
16. Look up the values for the heat of vaproization and the heat of fusion of water.
17. How much energy is needed to turn 250g of ice at zero degrees Celcius into liquid water at zero degrees.
18. How much energy is needed to raise 150 g of ice at 0 C to steam at 100 C
Define the following terms.
19. Heat of formation 20. specific heat capacity 21. molar heat capacity
22. Heat of fusion 23. heat of vaporization
Answers
1) 102,000 J 2) 1.97 J/g°C 3) 3500 g 4) 326.2 °C 5) 0.0712 J/g°C 6) 86.1 g 7) 31.8 °C