8. Why should you never determine the mass of a hot object? 9. Why is it necessary to calibrate a thermometer and volumetric glassware? 10. What is precision? 11. What is the density of an object with a mass of 1.583 g and a volume of 0.2009 mL? 12. Determining the mass of an object three times gave the following results: 9.2 g. 9.1 g, and 9.3 g. Find the mean mass and the average deviation from the mean. 13. Normal body temperature is 37.0 C. What is the corresponding Fahrenheit temperature? 14. What is the mass in kilograms of 680 mL of a substance that has a density of 0.930 g/mL? 15. An object has a mass of exactly 5 g on an analytical balance that has an accuracy of 0.1 mg. To how many significant figures should this mass be recorded