1: Explain how you can use Boyle’s Law to determine the new volume of
gas when its pressure is increased from 270 kPa to 540 kPa? The original
volume of gas was 1 L. Assume the temperature and number of particles are constant. What is the new volume?
Boyle's Law of gases: At constant temperature, the volume of a gas is inversely proportional to the pressure of the gas.
This is pV = constant. Then 1 L 270 kPa = x 540 kPa => x = 1L*270 kPa /540 kPa = 0.5 L
2: What are three common clues that a chemical change has occurred?
- Change of color
- Production of bubles
- Change of temperature
- Production of odors / smell
- Formation of precipitates (solids)
3: You have a sealed glass jar full of air. If you put it in the freezer, what happens to the gas pressure in the jar?
The pressure decreases, according to Gay-Lussac, at constant volume, the pressure and the temperaure of a gas are proportional.
Then at lower temperature (inside the freezer) the pressure in the jar will decrase.
4: Name and describe the phase change that occurs when solid carbon
dioxide (dry ice) is placed in an open container at room temperature.
This change of phase is called Sublimation. The solid passes directly to gas state, without passing by the liquid state.
