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Thermochemistry. Review. Review for Thermochemistry Test Define the following: Temperature Exothermic Endothermic Specific Heat Heat of Fusion Heat of Vaporization. 1. Matching: 1.Potential Energy A. Energy required for a
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Thermochemistry Review
Review for Thermochemistry Test Define the following: Temperature Exothermic Endothermic Specific Heat Heat of Fusion Heat of Vaporization
1. Matching: 1.Potential Energy A. Energy required for a reaction to occur. 2.Kinetic Energy B. Energy within the nucleus of the atom. 3.Chemical Energy C. Stored Energy 4.Activation Energy D. Energy required to break or form bonds. 5.Nuclear Energy E. Energy in Motion
2. Is the following reaction endothermic or exothermic? C + O2 CO2 + energy
3. Is the following an example of an Endothermic or Exothermic reaction? H2(g) + F2(g) 2 HF H = -542 kJ
4. Is the an Exothermic graph or Endothermic graph? What is Ea?
Remember: If is says absorbs, that means the Joules are positive. If it says releases, the Joules will be negative. 5. A 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes from 25°C to 175°C. Calculate the specific heat capacity of iron. Q = mass x C x (Tf – Ti)
6. How many joules of heat are needed to raise the temperature of 10.0 g of aluminum from 22°C to 55°C, if the specific heat of aluminum is 0.90 J/g°C? Is this an endothermic or exothermic reaction?
7. What is the specific heat of silver metal if 55.00 g of the metal absorbs 47.3 calories of heat and the temperature rises 15.0°C? Is this an Endothermic or Exothermic reaction?
9. Carbon tetrachloride can be formed by reacting chlorine with methane: CH4 + 2 Cl2 CCl4 + 2 H2 Given that the heat of formation of methane is –75 kJ/mol and the heat of formation of carbon tetrachloride is –135 kJ/mol, determine the heat of the reaction. Remember: Diatomics are “0”
10. When potassium chloride reacts with oxygen under the right conditions, potassium chlorate is formed: 2KCl + 3O2 2KClO3 Given that the heat of formation of potassium chloride is –436 kJ/mol and the heat of formation of potassium chlorate is –391 kJ/mol, determine the heat of the reaction. Remember: Diatomics are “0”
11. Relate a System and its Surroundings to Heat and Work. When is it positive and when is it negative?
12. 300 grams of ethanol at 10 °C is heated with 14640 Joules of energy. What is the final temperature of the ethanol?Useful information:The specific heat of ethanol is 2.44 J/g·°C.
13. The heat content of the products of the forward reaction is about how many kilojoules.
3 H2(g) + N2(g) <--> 2 NH3(g 15. When extra NH3 is added to the following system at equilibrium: A. In order to restore equilibrium, the reaction shifts left, toward reactants B. In order to restore equilibrium, the reaction shifts right, toward products C. No change occurs
3 H2(g) + N2(g) <--> 2 NH3(g) 16. When N2 is removed from the following system at equilibrium: A. No change occurs B. In order to restore equilibrium, the reaction shifts right, toward products C. In order to restore equilibrium, the reaction shifts left, toward reactants
17.Calculate DH for the reaction 4 NH3 (g) + 5 O2 (g) 4 NO (g) + 6 H2O (g), from the following data.
18. Determine the final temperature when a 25.0 g piece of iron at 85.0 °C is placed into 75.0 grams of water at 20.0 °C. The Specific Heat of Fe is .45. This is reversed to represent loss of heat. Q = -Q Mass x C x (Tf – Ti) = Mass x C x (Ti - Tf) Heat gained by Water = Heat lost by Metal
19. How many KJ of heat are produced when 5g of Al react with excess Cl2? 2 Al + 3 Cl2 2 AlCl3 H= -1408 KJ 1 mole Heat KJ Grams x ----------- x ------------------- MM (g) moles in reactions
