Chapter 1, Problem 1.97E

Many times errors are expressed in terms of percentage. The percent error is die absolute value of the difference of the true value and the experimental value, divided by the true value, and multiplied by 100. Percenterror=truevalue-experimentalvaluetruevalue100 Calculate the percent error for the following measurements. a. The density of an aluminum block determined in an experiment was 2.64 g/cm3. (True value 2.70 g/cm3.) b. The experimental determination of iron in iron ore was 16.48%. (True value 16.12%.) c. A balance measured the mass of a 1.000-g standard as 0.9981 g.

When a marble is dropped into a beaker of water, it sinks to the bottom. Which of the following is the best explanation? a. The surface area of the marble is not large enough to be held up by the surface tension of the water. b. The mass of the marble is greater than that of the water. c. The marble weighs more than an equivalent volume of the water. d. The force from dropping the marble breaks the surface tension of the water. e. The marble has greater mass and volume than the water. Justify your choice, and for choices you did not pick, explain what is wrong about them.

The beakers shown below have different precisions. a. Label the amount of water in each of the three beakers to the correct number of significant figures. b. Is it possible for each of the three beakers to contain the exact same amount of water? If no, why not? If yes, did you report the volumes as the same in part a? Explain. c. Suppose you pour the water from these three beakers into one container. What should be the volume in the container reported to the correct number of significant figures?