III. Concentration of products A. I, II, and III B.Both l and III C, Both II and
ID: 1041582 • Letter: I
Question
III. Concentration of products A. I, II, and III B.Both l and III C, Both II and ? D.11 3. In the combustion of ethane, 2 ?,He(g) + 7 O2(g)--4 COdg) + 6 H20(g), which reactant has the lowest rate of disappearance? A. C2H B. H2O C. O2 D. CO2 E. C2Hs and O have the same rate of disappearance. 4. In the following reaction addition of 0.05 moles of B, produces: A. Equilibrium shifts to the formation of C(-) B. Equilibrium shifts to the formation of A ( C. Equilibrium shifts to the consumption of C) D. Equilibrium shifts to the production of B () E. The reaction is endothermic 5. If the reaction quotient Q has a smaller value than the related equilibrium constant, K, A. the reaction is at equilibrium. B. the reaction will release heat to achieve equilibrium. C. the reaction will continue to make more products. D. the reaction will consume products and make reactants. E. the value of K will increase until it is equal to Q 6. In the equilibrium expressions, the concentrations of pure solids and liquids A. have the assigned value of one. B. are treated as any other solute. C. have constant values, cs and c.D. are determined from density and molar mass. E. have the assigned value of zero. CHEM-1043-P3Explanation / Answer
Ans. #3. Molar mass of C2H6 is 30.0 g/mol, and that of O2 is 32.0 g/ mol. Following stoichiometry of balanced reaction, 7 moles of O2 is consumed per 2 mol of ethane.
That is, if ethane is being consumed at a rate of 1 mol (=30.0 g) per second, then O2 would be at a rate of 3 moles (112.0 g) per second.
So, the rate of O2 consumption is greater than that of ethane.
# So, correct option is- C. O2
#4. Following Le Chatelier’s principle, addition of a reactant to the equilibrium mixture shifts the equilibrium towards formation of products.
So, correct option is – A.
#5. Correct option is- C. When Q < Keq, the reaction will continue to make more products.
A Q <Keq means that the concentration of product is less than that at its equilibrium values. So, following Le Chatelier’s principle, the reaction proceeds in forward direction to form more product and restore the equilibrium.
#6. Correct option A. Have the assigned value of one.
The concentration of pure solids and liquid is taken unity (1).