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Unformatted text preview: burgin (lcb626) – Pre-lab 9 – anderson – (53245) 1 This print-out should have 6 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 1.0 points Why is it important to calibrate the pH meter before use? Which buffers are we going to use for the calibration? Choose the best answer below. 1. The pH meter has to be calibrated be- cause pH is a log scale, not a linear scale, and without calibration, the pH meter would mea- sure values on a linear scale. The standards we will be using are pH 10, pH 7, and pH 4. 2. The pH meter has to be calibrated in order to prime it with hydrogen ions and hy- droxide ions, otherwise we would get no read- ing at all for our samples. We will be using H + and OH- standards. 3. The pH meter has to be calibrated be- fore use because otherwise it would be uncal- ibrated and calibration is necessary to avoid uncalibrated measurements. The standards we will be using are calibration standards. 4. The pH meter has to be calibrated so it has time to warm up before use, because pH is temperature dependent. We will be using room temperature standards for this experiment. 5. The pH meter has to be calibrated us- ing known standards to ensure it is giving accurate readings before we use it to measure sample pH values. The standards we will besample pH values....
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This note was uploaded on 10/25/2010 for the course CH 204 taught by Professor Leytner during the Spring '08 term at University of Texas.
- Spring '08