Chap 3, sec 4
List several properties of gases:
-gases are fluids -their particles move rapidly in all directions -they expand to fill their containers -they spread out easily and mix with one another -they have low densities and are highly compressible -they are mostly empty space -many are colorless and odorless
Explain why the volume of a gas can change.
Attraction between gas particles is not strong so the volumes of a gas can easily change
Identify which gas law: an increase in volume, decrease in pressure
Boyle's law
Which gas law is represented by the curved graph? (y-axis is volume, y-axis is pressure)
Boyle's law
Identify which gas law: a decrease in temperature, decrease in volume
Charle's law
Which gas law would a straight line graph represent? (y-axis is volume, x-axis is temperature)
Charles's Law
What happens to a fixed sample of gas when its temperature changes
Either pressure of volume must also change. Alternatively, both may change. The amplitude and direction of the changes depends on the original temperature change.
State Boyle's law:
For a fixed amount of gas at a constant temperature, the volume of a gas increases as the gas's pressure decreases. Likewise, the volume of a gas decreases as the gas's pressure increases.
Is the relationship proportional in the bottom graph? (curved downward)
No, because the graph is not a straight line
Express Boyle's law in mathematical terms.
P1V1 = P2V2
If the pressure in a tire increases what is happening to temperature? (volume is constant)
Temperature is increasing
Gas particles exert pressure by hitting the walls of a balloon. What happens if pressure becomes too great?
The balloon will pop
If the pressure exerted on a 300.0 mL sample of hydrogen gas at a constant temperature is increased from 0.500 kPa to 0.750 kPa, what will be the final volume of the sample?
V2 = P1V1/P2 = (0.500 atm x 300.0 mL)/0.750 atm = 200 mL
A sample of oxygen gas has a volume of 150 mL at a pressure of 0.947 kPa. If the temperature remains constant, what will the volume of the gas be at a pressure of 1.00 kPa?
V2 = P1V1/P2 = (o.947 atm x 150 mL)/1.000 atm = 142 mL
What two variables are related by Boyle's law?
Volume and pressure
What two variables are related by Charles's Law?
Volume and temperature
Gay-Lussac's law relates the temperature of a gas to its _____.
pressure
Charles's law relates the volume of a gas to its _____.
temperature
Why do gases have low densities?
Gases have low densities because their particles are so far apart
Identify which gas law: a increase in pressure, increase in temperature
Gay-Lussac's law
A flask contains 155 cm3 of hydrogen at a pressure of 22.5 kpa. Under what pressure would the gas have a volume of 90.0 cm3 at the same temperature?
P2= P1V1/V2 = (22.5 kPa x 155 cm3)/90.o cm3 = 38.8 kpa
What two variables are related by Gay-Lussac's Law?
Pressure and temperature
Compare and contrast the physical properties of solids, liquids, and gases
Solids have molecules fixed in relation to each other, Liquids have molecules capable of sliding capable of sliding past each other, but still stick together. Gases have molecules that are rarely in contact with each other. A substance as a solid has a definite volume and shape. The same substance as a liquid has a definite volume but takes the shape of its container. The same substance as a gas has no definite shape or volume.
Is the relationship shown by the curve in the bottom graph a direct relationship of an inverse relationship?
The slop is curved downward, so it shows an inverse relationship
Boyle's law relates the pressure of a gas to its ______.
volume