Question :
11.The formation of rust (Fe2O3) an exposed piece of metal : 1318409
11.The formation of rust (Fe2O3) on an exposed piece of metal typically takes several months. Which of the following statements is NOT a reasonable assumption about this chemical reaction?
4Fe(s) + 3O2(g) ? 2Fe2O3(s)
A) The reaction has a low reaction rate.
B) The reaction has low activation energy.
C) The rusting of iron would occur faster in the warmer summer months than in the cooler winter months.
D) The rusting of iron would occur slower at higher altitudes where the concentration of oxygen is lower.
E) Adding a catalyst would increase the rate of the formation of rust.
12.The rate of a chemical reaction increases with an increase in temperature. Which of the following correctly explains why?
A) At higher temperatures, the activation energy is increased.
B) At higher temperatures, the activation energy is decreased.
C) At higher temperatures, more reactant molecules are present and collisions occur more frequently.
D) At higher temperatures, reactant molecules move faster, collide more often, and produce more effective collisions.
E) At higher temperatures, a catalyst is usually present.
13.What is the equilibrium constant expression for the reaction shown below?
MgCO3(s) MgO(s) + CO2(g)
A)
B)
C)
D)
E)
14.The rate of a chemical reaction increases with an increase in concentration of one or more of the reactants. This is best explained by which of the following statements?
A) The increased concentration of reactants increases the temperature of the molecules.
B) The increased concentration of the reactants increases the activation energy of the reaction.
C) The increased concentration of the reactants increases the speed of the molecules.
D) The increased concentration of the reactants increases the frequency of effective collisions.
E) The increased concentration of reactants decreases the activation energy.
15.For the reaction shown below, Keq=2×1011. Which of the following statements concerning this system at equilibrium is true?
2CO(g) + O2(g) 2CO2(g)
A) The equilibrium lies to the left.
B) The equilibrium solution contains equal amounts of CO, O2, and CO2.
C) The reaction is very fast, due to the high value for Keq.
D) The equilibrium solution contains predominantly CO2.
E) The equilibrium system contains almost twice as many reactant molecules as product molecules.
16.What is the name and symbol of the thermodynamic quantity that represents the heat absorbed or liberated in a chemical reaction at constant pressure?
A)Enthalpy Change, ?HD)Both A and B are correct.
B)Entropy Change, ?SE)None of the choices are correct.
C)Free Energy Change, ?G
17.What thermodynamic quantity is the ultimate predictor of reaction spontaneity?
A)Enthalpy Change, ?HD)Both B and C are correct.
B)Entropy Change, ?SE)None of the choices are correct.
C)Free Energy Change, ?G
18.What instrument is used for measuring the heat energy absorbed or released in a chemical reaction?
A) thermometer B) calorimeter C) thermos D) balance E) scale
19.How many small calories are equivalent to one nutritional Calorie?
A) 10 B) 100 C) 1,000 D) 10,000 E) 100,000
20.A carbohydrate sample weighing 0.235 g was found to have a fuel value of 3.84 kJ. What is the fuel value of one gram of this carbohydrate, in nutritional Calories?
A) 3,910 Cal B) 0.535 Cal C) 16.3 Cal D) 643 Cal E) 3.91 Cal
