chem. help~

3) Gases are compressible because the molecules are very spaced out (contain a lot of empty space between molecules), therefore, it is easy to compress gases into a smaller volume.

8) Water cools as it evaporates because this reaction is an endothermic reaction. Energy is absorbed by the water molecules to change from liquid state to gas state. The energy absorbed are taken from the surround environment, thus, the surrounding will cool while the water evaporates.

10) Gas laws are based on the concept of "ideal gases". Real gases may differ from ideal gas conditions because:

a) they have real volume
b) the collisions between the gas molecules are not completely elastic

2007-05-25 06:38:04 補充：
7) Absolute zero is usually refers to as 0K, which is -273 Celsius. This is the lowest temperature possible. At this temperature, there is just empty space, with no motion/energy present. This state is extremely difficult to achieve.

6 ) Dalton's law of partial pressure
1. total pressure = the sum of partial pressures
2. Partial pressure = mole fraction x total pressure