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Unformatted text preview: silva (jrs4378) Homework 5 sutcliffe (51060) 1 This print-out should have 26 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. Please note: This HW may seem to have more questions but a lot of them are very quick practice problems on simpler concepts. Also note p just equals negative log of so we can have pH, pOH , pK a etc. 001 10.0 points Pick the name and formula that do NOT match. 1. HBrO 4 : perbromic acid 2. H 2 CrO 4 : chromic acid 3. HCN : hydrocyanic acid 4. H 2 PO 4 : phosphoric acid correct Explanation: Phosphoric acid is H 3 PO 4 . Brom ic acid is HBrO 3 . Per brom ic acid has one more oxygen atom, so its formula is HBrO 4 . HCN is hydrogen cyanide. In aqueous solu- tion, HCN is known as hydro cyan ic acid. CrO 2- 4 is the chrom ate ion. H 2 CrO 4 is chromic acid. 002 10.0 points Which of the following is NOT a property of bases? 1. Bases produce hydrogen ions, H + , when added to water. correct 2. Bases taste bitter. 3. Bases feel slippery. 4. Bases react with acids. 5. Bases make indicators change colors. Explanation: Bases have a bitter taste and have a slip- pery feel. They also react with acids to form salts. Both acids and bases give chracter- istic colors with indicators. However, bases produce hydroxide ions, OH- , in aqueous so- lution, not hydrogen ions, H + . 003 10.0 points Which one of the following pairs of acids and their conjugate bases is INCORRECTLY matched? 1. HF : F- 2. H 2 O : OH- 3. HClO : ClO- 4. NH + 4 : NH- 2 correct 5. H 3 O + : H 2 O Explanation: An acid is a proton donor and a base is a proton acceptor. The only difference between the acid and its conjugate base is that the base has one less H atom. NH- 2 has two fewer H atoms than the NH + 4 ; therefore, it is incorrectly matched. 004 10.0 points HCN is classified as a weak acid in water. This means that it produces 1. a relatively small fraction of the maximum number of possible hydronium ions. correct 2. a relatively large fraction of the maximum number of possible hydronium ions. 3. no hydronium ions. 4. 100% of the maximum number of possible hydronium ions. Explanation: In water only a small percentage of a weak acid hydrolyzes, producing H 3 O + ions....
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This note was uploaded on 10/23/2010 for the course CH 51060 taught by Professor Sutcliffe during the Fall '10 term at University of Texas at Austin.
- Fall '10