Worksheet I.4: Density Calculations Name: Date: Table 1. Densities of common substances in g/ml Mercury 13.6 Alcohol 0.789 Lead 11.4 Ice 0.917 Aluminum 2.70 Air 0.00120 Use the information above to answer all the questions below. Complete each section of each problem. 1. A nail has a mass of 14.2 g and a volume of 1.8 ml. Calculate its density. 2. A drop of mercury has volume of 1.5 ml. Calculate its mass.
3. The mass of 25 ml of corn oil is 24.8 g. Calculate its density. 4. A sample of air has a mass of 775 g. Calculate its volume.
5. A gold ring has a mass of 43.43 g and a volume of 2.25 ml. Calculate its density. 6. An ice cube in your freezer has a volume of 34 ml. Calculate its mass.
7. A block of wood is 5.5 cm long, 2.3 cm wide, and 1.25 cm tall. It has a mass of 33.4 g. Calculate its density. 8. An aluminum bike has a mass of 8.1 kg. Calculate its volume.
You and your lab partner are asked to measure the density of four different rectangular prisms. You use different rulers to measure the dimensions of each object. Calculate the largest and smallest volume of each object based on the uncertainty in each measurement. Table 2: Volume Range based on Uncertainty in each measurement Object Length (cm) Width (cm) Height (cm) Smallest Volume (cm 3 ) Largest Volume (cm 3 ) A. 4.30 +/- 0.05 2.45 +/- 0.05 0.85 +/- 0.05 B. 2.5 +/- 0.5 2.0 +/- 0.5 1.0 +/- 0.5 C. 18 +/- 1 6.2 +/- 0.1 4.25 +/- 0.05 D. 12.40 +/- 0.05 4.95 +/- 0.05 1.20 +/- 0.05 In the second part of the lab, you measure the mass of each object on a triple beam balance. Use the masses in the table below and the volumes you calculated in the table above to calculate the minimum and maximum density of each object. Table 3. Mass and Density of each object Object Mass (g) Smallest Density Largest Density A. 4.30 +/- 0.05 B. 12.25 +/- 0.05 C. 18.00 +/- 0.05 D. 12.55 +/- 0.05
Based on the results recorded in Table 3 above, complete Table 4. Read the directions below in order to complete each column. Table 4: Uncertainty expressed as a percentage of the measurement. Object Average density Difference between average and extreme Difference expressed as a percentage of the average Level of uncertainty (acceptable? or too large?) A. B. C. D. I. Average Density: add the smallest density and largest density of each object and divide by two. II. Difference between average and extreme: subtract the average density (calculated above in part I.) from the largest density. Or, subtract the smallest density from the average density. Both calculations should produce the same number. III. Difference as expressed as a percentage of the average: Divide the difference (calculated above in Part II.) by the average density and multiply the result by 100. IV. Level of Uncertainty: any measurement or result in science with less than 5% uncertainty is considered acceptable. The percentage calculated in part III. above can be considered the uncertainty. Based on this percentage, decide whether the calculated value for the density is acceptable or not.