1. Label five test tubes 1, 2, 3, 4, and 5, and place them in a test-tube rack.
2. ^^ CAUTION Always cut in a direction away from your body. Use a scalpel to cut a firm, cooked egg white into fine pieces.
3. Using the balance, measure and place equal amounts (about 6 g) of the fine egg white sample into each test tube, as shown in the illustration above.
CAUTION Put on safety gog-V ^r gles and a lab apron. If you get hydrochloric acid solution on your skin or clothes, wash it off at the sink while calling to your teacher. If you get any solutions in this investigation in your eyes, immediately flush them out at the eyewash station while calling to your teacher. Use a clean graduated cylinder to add the solutions listed below to the test tubes. Rinse the cylinder between additions so that you do not contaminate the samples.
• test tube 3—10 mL of hydrochloric acid
• test tube 4—5 mL of pepsin solution and 5 mL of sodium bicarbonate solution
• test tube 5—5 mL of pepsin and 5 mL of hydrochloric acid
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