Homework Help Chapter 8

Page 181
2. Look up coefficient of linear expansion for steel in the back of the book; use equation on p. 172
5. This substance is a liquid at this temperature. Look up its volume expansion coefficient and use equation on p. 173
6. (a) STP is standard temperature and pressure, 273 K and 1 atm. Use Charles' law, p 176. (b) Same 2 L of gas, but now pressure varies: use Boyle's law, p. 178. (c) use pressure - density relationship on p 178
17. Use combined gas law, p 179. No need to actually calculate using given quantities if you just use the symbols and the changes given. (V' = 4V)

Page 187
1. Use Q = mcDT
3. Use Q = mcDT, look up specific heat for aluminum (don't worry about which one)
4. Heat lost by warm water equals heat gained by cold water. Express change in temperature for each term by using difference between starting temperature (given) and final temperature (unknown).
5. Typical calorimeter problem. Water and calorimeter have the same range of temperatures. Look up specific heat for brass and aluminum. Heat lost by brass equals heat gained by calorimeter and water.
6. Use Q = mcDT, solve for c.

Page 197
1. Use heat of fusion for ice, 334 J for every gram that melts.
4. Good calorimeter problem with a phase change. Look up specific heat of copper. Heat lost by copper and warm water equals heat lost due to melting ice and warming resulting cold water to final temperature. Remember, if a phase change is involved, there will be two terms in the equation, one for the heat absorbed (or released) during the phase change, and one for the temperature change of the result of the phase change (in this case, zero degree water). (88.8 g)
6. Use heat of vaporization of water, 2260 J for every gram that vaporizes.
8. See chart on p. 196. For every gram, 2260 J are released when it condenses, 4.19J/degree are released as it cools, and 334 J released as it freezes.
11. Harder problem because final temperature is not given, but no calorimeter here. Setup is the same, heat lost by warm water equals heat gained by ice; one term for melting of the ice and one for warming the resulting 0 degree water to the final temperature. (0.14 ^oC)