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Unformatted text preview: Chemistry 112 Test # 2 1. A 25.0-mL sample of 0.100 M HCl is mixed with 20.0 mL of 0.100 M NaOH. The pH of the resulting solution will be nearest 2: excess strong acid. Exact answer: 0.5 mmol HCl/45 mL = 0.011M; pH = 1.95. 2. The HNO 3 molecule does not exist in aqueous solution because it dissociates: HNO 3 + H 2 O H 3 O + + NO 3- . This reaction goes to completion because HNO 3 is a stronger acid than H 3 O + . 3. The aminoacid glycine is titrated with base, giving a titration curve as shown. At the point indicated by the arrow, which species does the solution contain? A B C D pH mL added NaOH (A) only C O N H 3 + CH 2 OH (B) C O N H 3 + CH 2 OH and C O N H 3 + CH 2 O- (C) only C O N H 3 + CH 2 O- (D) C O N H 3 + CH 2 O- and C O N H 2 CH 2 O- 4. The dissociation constant for ammonium, NH 4 + , is K a = 5.6 10 10 : NH 4 + (aq) H + (aq) + NH 3 (aq). In a solution, [NH 4 + ] = 0.100M and [NH 3 ] = 0.100M. What is the [H + ] ? 5.6 10-10 M 5. HCN is a weak acid with K...
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This note was uploaded on 06/01/2008 for the course PHYS 117 taught by Professor Hendrick during the Spring '08 term at Millersville.
- Spring '08