Unit 3

SCH4U ~ UNIT 3 TEST INSTRUCTIONS FOR SUBMISSION ONLINE VIA DROPBOX (Please SUBMIT only ONE file) Handwritten Sections: Knowledge and Understanding and Inquiry Typed (on Computer) Sections: Communication and Application MULTIPLE CHOICE  Select the best possible answer for each question below. 1. A chemical system in which both energy and matter can flow into or out of a system is described as: a. a closed system d. a chemical system b. an open system e. none of the above c. an isolated system 2. The specific heat capacity of a substance is a. the quantity of heat required to raise the temperature of one mole of a substance by one degree Celsius or Kelvin b. the quantity of heat required to raise the temperature of one gram of a substance by one degree Celsius or Kelvin c. the quantity of heat required to raise the temperature of one molecule of a substance by one degree Celsius or Kelvin d. the quantity of heat required to raise the temperature of a substance by one degree Celsius or Kelvin e. none of the above 3. The heat released during the combustion of C 3 H 8 (g) (propane) to produce CO 2 (carbon dioxide) gas and water vapour is 2222 kJ/mol of C 3 H 8 (g). Which of the following is the correct chemical equation for the reaction? a. C 3 H 8 (g) + 5O 2 (g)  3CO 2 (g) + 4H 2 O (g)  H = +2222 kJ b. C 3 H 8 (g) + 5O 2 (g) + 2222 kJ  4H 2 O (g) + 3CO 2 (g) c. C 3 H 8 (g)+ 5O 2 (g)  3CO 2 (g) + 4H 2 O (g) + 2222 kJ d. 3CO 2 (g) + 4H 2 O(g)  5O 2 (g) + C 3 H 8 (g)  H = –2222 kJ e. none of the above 4. The exponents determined for the overall rate law equation a. must be the same as the coefficients of the reaction b. can be multiplied together to determine the rate of the reaction c. can be added together to determine the rate of the reaction d. can be added together to determine the order of the reaction e. are independent of each other

5. A rate of reaction is usually obtained by measuring a. the rate at which products are consumed b. the rate at which reactants are produced c. the rate at which reactants are consumed d. the temperature of the solution e. the mass and volume of the products 6. If for the reaction , the rate law is determined to be , then a. doubling the concentration of Y will double the rate of the reaction b. halving the concentration of Y will double the rate of the reaction c. doubling the concentration of X will double the rate of the reaction d. halving the concentration of X will double the rate of the reaction e. only changes to the concentration of Y will affect the rate of the reaction 7. We can communicate the energy changes obtained from empirical studies by a. including an energy value as a term in the thermochemical equation b. writing a chemical equation and stating its enthalpy change c. stating the molar enthalpy of a specific reaction d. drawing a chemical potential energy diagram e. any of the above 8. Which of the following is not a factor that controls the rate of the reaction? a. chemical nature of the reactants d. surface area b. concentration of the reactants e. temperature c. the number of products formed 9. The amount of energy required for a reaction to begin is known as a. enthalpy change d. kinetic energy b. reaction energy e. potential energy c. activation energy 10. An exothermic reaction is one where a. heat is transferred from the surroundings into a system b. heat is transferred from a system into the surroundings c. kinetic energy is transformed into potential energy d. there is no transfer of heat e. none of the above

13. The molar enthalpy of a solution of ammonium chloride is + 14.8 kJ/mol. What would be the final temperature of a solution in which 40.0g of ammonium chloride is added to 200.0mL of water, initially at 25  C? [4 marks] 14. Given the following information: [4 marks]  2ClF 3 (g) + 2NH 3 (g)  N 2 (g) + 6HF (g) + Cl 2 (g)  H  = -1196kJ  N 2 H 4 (l) + O 2 (g)  N 2(g) + 2H 2 O (l)  H  = -622kJ  4NH 3 (g) + 3 O 2(g)  2 N 2 (g) + 6 H 2 O (l)  H  = -1530kJ determine the  H  for the following reaction: 3N 2 H 4(l) + 4ClF 3 (g)  3N 2 (g) + 12HF (g) + 2 Cl 2 (g)

15. Consider the preparation of pentanol from the reaction of pentene and water. Estimate  H for this reaction, using bond energies. [4 marks] 16. Sketch a potential energy diagram for an endothermic reaction. Label the axes, reactants, products,  H  for the overall reaction, as well as the Ea for the reaction. [3 marks]

C O M M U N I C A T I O N 19. Comment on the validity of the following statements: a) The magnitude of the rate constant (k) is independent of the temperature. [2 marks] Valid / Invalid (circle one) Explain: b) In general enzymes/catalysts lower the activation energy needed for a reaction to occur, this in turn can alter the enthalpy change of the reaction. [2 marks] Valid / Invalid (circle one) Explain: c) Thermal energy is a form of potential energy that can be released to the surroundings. [2 marks] Valid / Invalid (circle one) Explain: d) Nuclear generating stations use fusion to release energy. [2 marks] Valid / Invalid (circle one) Explain:

A P P L I C A T I O N 20. Catalysts used in industry can work in two different ways. They are either adsorption catalysts or catalysts that form intermediate compounds. Research online each of these types of catalysts, and describe how they work in a few sentences. Give an example of a situation in which each is most useful and explain why. [4 marks] 21. A match can be applied to a lump of coal with little effect. However, the ignition of coal dust has caused many fatal mining explosions. Explain. [2 marks] 22. Many chefs keep a box of baking soda near their stoves in case a grease fire breaks out. Research the reaction that occurs when baking soda is heated, and explain how it is effective for putting out grease fires. Use equation(s) to explain . [2 marks]