(Solved): 37. When gasoline burns, which of the following is a correct description of the process? A. The rea ...

37. When gasoline burns, which of the following is a correct description of the process? A. The reaction is exothermic; $\Delta H^{\circ }<0$ B. The reaction is endothermic; $\Delta H^{\circ }>0$ C. The reaction is endothermic; $\Delta H^{\circ }<0$ D. The reaction is exothermic; $\Delta H^{\circ }>0$ E. None of these statements is correct 38. Which statement is true about reaction rate for the reaction: $A+B\rightleftharpoons C+D$ ? A. When the forward reaction rate is equal to the reverse reaction rate, the volume of the mixture will decrease B. When the forward reaction rate is greater than the reverse reaction rate, the temperature of the mixture will go down C. When the forward reaction rate is smaller than the reverse reaction rate, the temperature of the mixture will go up D. When the forward reaction rate is equal to the reverse reaction rate, both forward and reverse reactions will stop E. When the forward reaction rate is equal to the reverse reaction rate, there will be no change in the concentrations of reactants and products 39. After initiating a reaction in a coffee cup calorimeter, the temperature of the water was observed to decrease by several degrees. Based on this information, the reaction is A. accelerated by a catalyst B. Exothermic C. Endothermic D. $\Delta \mathrm{S}>0$ E. $\Delta \mathrm{S}<0$ 40. $10\mathrm{g}$ of octane is burned in a bomb calorimeter containing $100\mathrm{g}$ of ${\mathrm{H}}_2\mathrm{O}$. How much energy was released (in calories) if the temperature increased by $10^{\circ }\mathrm{C}$. (note: specific heat of water is $1\mathrm{cal}/\mathrm{g}/{}^{\circ }\mathrm{C}$ ). A. $1000\mathrm{cal}$ B. $100\mathrm{cal}$ C. 1 cal D. $10\mathrm{kcal}$ E. $100\mathrm{kcal}$