HW11SOL - Moore, Robert Homework 11 Due: Apr 25 2007,...

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Moore, Robert – Homework 11 – Due: Apr 25 2007, midnight – Inst: McCord 1 This print-out should have 15 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. The due time is Central time. 001 (part 1 oF 1) 10 points The rate oF the reaction 2O 3 3O 2 is equal to 1. - Δ[O 3 ] Δ t . 2. - 1 3 Δ[O 2 ] Δ t . 3. + 1 2 Δ[O 3 ] Δ t . 4. - 1 2 Δ[O 3 ] Δ t . correct 5. - Δ[O 2 ] Δ t . Explanation: The rate oF a chemical reaction can either be expressed as the rate oF disappearance oF a reactant (as in this case) or as the rate oF appearance oF a product. However, this rate is multiplied by the inverse oF the coeF- fcient oF the species in question. The nega- tive sign here reminds us that as the reaction progresses, this species is consumed and de- creases in concentration. 002 (part 1 oF 1) 10 points One oF the reactions used commercially to produce hydrogen gas is H 2 O(g) + CO(g) H 2 (g) + CO 2 (g) . A proper expression For the rate oF this reaction could be 1. - Δ[H 2 O] Δt . correct 2. - Δ[CO 2 ] Δt . 3. + Δ[CO] Δt . 4. - Δ[H 2 ] Δt . Explanation: The rate oF a chemical reaction can either be expressed as the rate oF disappearance oF the reactant (as in this case) or as the rate oF the appearance oF the product; however, this rate is multiplied by the inverse oF the coe±cient oF the species in question. The negative sign here reminds us that as the reaction progresses, this species is consumed and goes down in concentration. 003 (part 1 oF 1) 10 points When the reaction 3NO(g) N 2 O(g) + NO 2 (g) isproceeding underconditionssuchthat0.015 mol/L oF N 2 O is being Formed each second, the rate oF the overall reaction is ? and the rate oF change For NO is ? . 1. 0.015 M · s - 1 ; +0.045 M · s - 1 2. 0.015 M · s - 1 ; - 0.045 M · s - 1 correct 3. none oF the other answers is correct 4. 0.015 M · s - 1 ; - 0.005 M · s - 1 5. 0.030 M · s - 1 ; - 0.005 M · s - 1 Explanation: Notice that three moles oF NO are required to make one mole oF N 2 O in this reaction, so the rate oF disappearance oF NO (which has a negative sign) is three times the rate oF appearance oF N 2 O. 004 (part 1 oF 1) 10 points Which oF the Following does not a²ect the rate oF a reaction? 1. the presence oF a catalyst 2. the value oF Δ H rxn correct
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Moore, Robert – Homework 11 – Due: Apr 25 2007, midnight – Inst: McCord 2 3. the temperature of the reactants 4. the value of E a Explanation: Δ H is a state function; it is independent of the path. 005 (part 1 of 1) 10 points Consider the irreversible reaction A + 2B 3C . Which of the following correctly expresses
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HW11SOL - Moore, Robert Homework 11 Due: Apr 25 2007,...

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