Answers to Selected Exercises
The answers listed here are from the Complete Solutions Guide, in which rounding is carried out at each intermediate step in a calculation in order to show the correct number of signi?cant ?gures for that step. Therefore, an answer given here may differ in the last digit from the result obtained by carrying extra digits throughout the entire calculation and rounding at the end (the procedure you should follow).
19. A law summarizes what happens, e.g., law of conservation of mass in a chemical reaction or the ideal gas law, PV nRT. A theory (model) is an attempt to explain why something h…(생략)
appens. Dalton’s atomic theory explains why mass is conserved in a chemical reaction. The kinetic molecular theory explains why pressure and volume are inversely related at constant temperature and moles of gas. 21. The fundamental steps are (1) making observations; (2) formulating hypotheses; (3) p