Homework Apply 1-5 Measure for Measure

1. Luis is performing an experiment with table salt. He uses an electronic balance with a digital display that reads masses to one tenth of a gram. Luis finds the mass of two samples. For each sample, the balance reads 1.2 g. Luis thinks the two samples have identical masses. Explain why this conclusion might not be true.

2. A laboratory procedure calls for three samples of baking soda. The mass of each sample should be 1.3 ± 0.1 g. Vicotoria, being a careful student, spends 10 minutes measuring out each sample, making sure the balance reads 1.300 g for each. Victoria is confident that she is doing a good work, but she runs out of time, and her teacher deducts points for bad lab technique. What was wrong with Victoria’s technique?

3. Maria and Sharna were analyzing the data from their lab report. Maria had calculated the mass of an aluminum block to be 31.80 g. Sharna reported that the true mass must fall in the range of 31.800 g to 31.801 g. Did Sharna correctly represent the uncertainty in their measurement? Explain.