Exam2Solutions - Johnson Chelsea Exam 2 Due Mar 7 2007 noon...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Johnson, Chelsea – Exam 2 – Due: Mar 7 2007, noon – Inst: Walker 1 This print-out should have 16 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. The due time is Central time. Read all oF the options beFore choosing one. There may be cases in which more than one response appears to be true. PICK THE RE- SPONSE THAT BEST answers the question asked. NOTE: Do not convert given ”atm” to torr. Solve using atm, just as we did on homework. 001 (part 1 oF 1) 13 points Which acid is weaker? 1. HNO 3 2. HNO 2 correct 3. They have the same strength. Explanation: HNO 3 is he stronger oxoacid; there is one more O atom attached to the N atom in HNO 3 than in HNO 2 . This makes the H O bond more polar (and thus more easily broken) in HNO 3 than in HNO 2 . 002 (part 1 oF 1) 13 points Which oF the Following salts produces a neu- tral solution when it is dissolved in water? 1. Li± 2. KCN 3. KCH 3 CO 2 4. NaClO 5. NaBr correct Explanation: 003 (part 1 oF 1) 13 points How much acetic acid ( K a = 1 . 8 × 10 - 5 ) must be used to prepare a liter oF solution having a pH oF 2.75? 1. 9.88 moles 2. 5.69 moles 3. 0.178 moles correct 4. 0.435 moles 5. 0.0101 moles Explanation: pH = - log[H + ] = 2 . 75 so [H + ] = log - 1 ( - 2 . 75) = 1 . 778 × 10 - 3 mol HA * ) H + + A - Subsitute [H + ] = [A - ] = 1 . 778 × 10 - 3 into the equation For K a : K a = [H + ][A - ] [HA] [HA] = [H + ][A - ] K a = ( 1 . 778 × 10 - 3 ) 2 1 . 8 × 10 - 5 0 . 178 mol 004 (part 1 oF 1) 11 points The state oF dynamic balance that exists when the Forward and reverse processes oF a re- versible reaction are occuring simultaneously at the same rate is called 1. equilibrium constant. 2. chemical equilibrium. correct 3. heterogeneous equilibrium. 4. mass action expression. Explanation: Chemical equilibrium is dynamic, with the Foward and reverse reactions occuring at the same rate.
Background image of page 1

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

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 5

Exam2Solutions - Johnson Chelsea Exam 2 Due Mar 7 2007 noon...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online