11. When a 0.817 g sample of a copper oxide is heated with excess hydrogen gas, 0.187 g of water is formed. What is the apparent formula of the copper oxide? (A) CuO (B) Cu2O (C) Cu2O3(D) CuO212. A reaction in which S and H are positive is expected to be
13. Which process or reaction has a positive H? (A) H2O(l) ---> H2O(s) (B) 2 CH3OH(l) + 3 O2(g) ----> 2 CO2(g) + 4 H2O(l) (C) CO2(s) ---> CO2(g) (D) 2 Na(s) + Cl2(g) ---> 2 NaCl (s) 14. For which process or reaction is S positive at 25 °C? (A) 2 NO2(g) ---> N2O4(g) (B) CO2(g) ---> CO2(s) (C) CH4(g) + 2 O2(g) ---> CO2(g) + 2 H2O(l) (D) 2 SO3(g) --- > 2 SO2(g) + O2(g) 15. For the reaction H2(g) + I2(s) ---> 2 HI(g) Hrxn= 53.0 kJ What will be the value of Hrxn(in kJ) for this reaction ? HI(g) ---> 1/2 H2(g) + 1/2 I2(s) 16. For the reaction of hydrogen peroxide and iodide ion in acid solution, represented by the equation: H2O2+ 3I¯ + 2H+---> I3¯ + 2 H2O these kinetic data are gathered: Initial Concentrations, M H2O2I¯ H+Initial Rate, M s¯1Exp. 1 0.010 0.010 0.00050 1.15 x 10¯6Exp. 2 0.020 0.010 0.00050 2.30 x 10¯6Exp. 3 0.020 0.020 0.00050 4.60 x 10¯6
Exp. 4 0.020 0.020 0.00100 4.60 x 10¯6What is the rate law for the reaction? 17. A small increase in temperature often causes a large increase in the rate of a chemical reaction. This effect is best attributed to (A) a decrease in the activation energy of the reaction (B) more frequent collisions at the higher temperature (C) the occurrence of more collisions with the needed energy (D) different reaction pathways at the higher temperature 18. Zinc metal reacts with excess HCl according to the equation: Zn(s) + 2H+(aq) + 2Cl¯(aq) ----> Zn2+(aq) + 2Cl¯(aq) + H2(g) Which change will increase the rate of evolution of H2? Changes in Reaction Conditions I. using zinc dust in place of chunks II. using 2 M HCl in place of 1 M HCl III. using 200 mL of 1 M HCl in place of 100 mL 19. Which of the indicated quantities in the reaction diagram will be affected by the addition of a catalyst?
20. Gases can be compressed more easily than liquids because
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- Reaction, H2O