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Unformatted text preview: saldana (avs387) Pre-lab 4 Lyon (90255) 1 This print-out should have 5 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points How many moles of phosphoric acid would one need to completely neutralize one mole of barium hydroxide? 1. 2/3 moles of phosphoric acid 2. 3/2 moles of phosphoric acid 3. 1/3 moles of phosphoric acid 4. 5/3 moles of phosphoric acid 5. 6/2 moles of phosphoric acid 6. 3/3 moles of phosphoric acid 002 10.0 points What is the main objective of Part 1 of the experimental procedure? What is the purpose of using KHP in this part of the experiment? 1. The main objective of Part 1 is to verify the color change of the phenolphthalein at the endpoint of the titration, since we will be relying on phenolphthalein in Part 2 and dont want to use it without verification. KHP is used because it is colorless when dissolved in water, and therefore does not interfere with the color change of the phenolphthalein. 2. The main objective of Part 1 is to deter- mine the concentration of the NaOH solution as accurately and precisely as possible. KHP is used as a titration standard because it is very pure, and can therefore yield highly ac- curate results for the NaOH concentration....
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- Spring '10