{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

HW8solutions

# HW8solutions - Niu(qn269 Homework 8 owers(53885 This...

This preview shows pages 1–3. Sign up to view the full content.

Niu (qn269) – Homework 8 – flowers – (53885) 1 This print-out should have 30 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. HW 8. Due 25 November 2008 at 11PM 001 10.0 points The rate of formation of oxygen in the follow- ing reaction is 2.28 M/s. 2 N 2 O 5 (g) 4 NO 2 (g) + O 2 (g) What is the rate of formation of NO 2 ? 1. 1.14 M/s 2. 2.28 M/s 3. 9.12 M/s correct 4. 0.57 M/s 5. 4.56 M/s Explanation: The NO 2 forms at 4 × the rate of the O 2 . 002 10.0 points Consider the reaction 2 NO 2 (g) + F 2 (g) 2 NO 2 F(g) rate = Δ[F 2 ] Δ t . What is another form of the rate of the reaction? 1. Δ[NO 2 F] Δ t 2. Δ[NO 2 F] 2 Δ t correct 3. Δ[NO 2 ] 2 Δ t 4. Δ[NO 2 ] Δ t 5. 2 Δ[NO 2 ] Δ t Explanation: 003 10.0 points Consider the concentration-time dependence as shown below for two first order reactions. [A] 0 Molar Concentration of Reactant Concentration −→ Time −→ Which reaction has the greatest t 1 / 2 ? 1. the reaction represented by the lower curve 2. the reaction represented by the upper curve correct 3. Unable to determine Explanation: 004 10.0 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[CO 2 ] Δt . 2. + Δ[CO] Δt . 3. Δ[H 2 O] Δt . correct 4. Δ[H 2 ] Δt . Explanation:

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Niu (qn269) – Homework 8 – flowers – (53885) 2 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 coefficient 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. 005 10.0 points What is the rate for the formation of Cu(s) in the reaction Cu 2+ (aq) + H 2 (g) Cu(s) + 2 H + (aq) if Δ[H + ] Δ t = 1 . 2 × 10 3 ? 1. 2 × 10 4 2. 2 . 4 × 10 3 3. 3 × 10 4 4. 1 . 2 × 10 3 5. 6 × 10 4 correct Explanation: 006 10.0 points What is the rate law for the reaction A + B + C D if the following data were collected? Exp [A] 0 [B] 0 [C] 0 Initial Rate 1 0.4 1.2 0.7 2 . 32 × 10 3 2 1.3 1.2 0.9 7 . 54 × 10 3 3 0.4 4.1 0.8 9 . 25 × 10 2 4 1.3 1.2 0.2 7 . 54 × 10 3 1. rate = 3 . 36 × 10 3 [A] 1 [B] 3 [C] 0 correct 2. rate = 1 . 79 × 10 3 [A] 0 [B] 2 [C] 1 3. rate = 1 . 49 × 10 3 [A] 0 [B] 3 [C] 1 4. rate = 4 . 48 × 10 3 [A] 1 [B] 2 [C] 1 5. rate = 5 . 37 × 10 3 [A] 1 [B] 3 [C] 0 Explanation: 007 10.0 points For a given reaction, the rate-law is 1. an equation in which reaction rate is equal to a mathematical expression involving con- centrations of reactants. correct 2. a constant of proportionality between re- action rate and the concentrations of reac- tants. 3. the sum of the powers to which reactant concentrations appear. Explanation: The rate law for a reaction A + B C + D is set up as Rate = k [A] x [B] y This is an expression involving the con- centrations. The constant of proportionality option is the rate constant k , while the sum of powers option is the order of reaction.
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}