University of Texas CH 302 McCord H06 - Acid-Base 1

University of Texas CH 302 McCord H06 - Acid-Base 1 -...

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

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: byrne (cmb3744) – H06: Acid-Base 1 – mccord – (51620) 1 This print-out should have 21 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points What is the hydroxide concentration [OH − ] in an aqueous solution in which the hydronium ion concentration [H 3 O + ] is 1 × 10 − 5 M? 1. 1 × 10 − 7 M 2. 1 × 10 − 14 M 3. 1 × 10 − 9 M correct 4. 1 × 10 − 5 M Explanation: [H 3 O + ] = 1 × 10 − 5 M K w = [H 3 O + ][OH − ] = 1 . × 10 − 14 [OH − ] = K w [H 3 O + ] = 1 . × 10 − 14 1 × 10 − 5 = 1 × 10 − 9 M 002 10.0 points Which of the following is true in pure water at any temperature? 1. [H 3 O + ][OH − ] = 1.0 × 10 − 14 2. pH = 7.0 3. [H 3 O + ] = [OH − ] correct 4. K w decreases with increasing tempera- ture. 5. pH = 7.0 or greater than 7.0 Explanation: K w is shown to INCREASE with increas- ing temperature. pH = 7 is only true when water is at 24 ◦ C. [H 3 O + ][OH − ] = K w , which increases with temperature. At high temperatures pH can be less than 7. Thus [H 3 O + ] = [OH − ] is the only case that is true. 003 10.0 points What is [H 3 O + ] when [OH − ] = 3 . 3 × 10 − 9 M? 1. 1 . × 10 − 7 M 2. 6 . 6 × 10 − 5 M 3. 3 . 3 × 10 − 9 M 4. 3 . 3 × 10 − 5 M 5. 3 . × 10 − 6 M correct Explanation: [OH − ] = 3 . 3 × 10 − 9 M K w = [H 3 O + ][OH − ] = 1 × 10 14 [H 3 O + ] = K w [OH − ] = 1 . × 10 14 3 . 3 × 10 − 9 = 3 . × 10 − 6 M 004 10.0 points What is [OH − ] when [H 3 O + ] = 8 . 2 × 10 − 5 M? 1. 6 . 3 × 10 − 9 M 2. 8 . 2 × 10 − 5 M 3. 1 . × 10 − 7 M 4. 1 . 2 × 10 − 10 M correct 5. 1 . 2 × 10 − 4 M Explanation: [H 3 O + ] = 8 . 2 × 10 − 5 M K w = [OH − ][H 3 O + ] = 1 . × 10 14 [OH − ] = K w [H 3 O + ] = 1 . × 10 14 8 . 2 × 10 − 5 = 1 . 2 × 10 − 10 M 005 10.0 points What is [OH − ] in a 0.0050 M HCl solution? 1. 2 . × 10 − 12 M correct byrne (cmb3744) – H06: Acid-Base 1 – mccord – (51620) 2 2. 1 . × 10 − 7 M 3. 5 . × 10 − 3 M 4. 1 . 0 M 5. 6 . 6 × 10 − 5 M Explanation: [OH − ] = 0 . 0050 M Since HCl is a strong acid, it completely dissociates and H + is 0 . 0050 M....
View Full Document

Page1 / 6

University of Texas CH 302 McCord H06 - Acid-Base 1 -...

This preview shows document pages 1 - 3. Sign up to view the full document.

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