Kinetic Molecular Theory
What type of motion do gas particles exhibit?
Random motion in all directions
What happens to the frequency of collisions when volume increases at constant temperature?
Collision frequency with the walls decreases as volume increases at constant temperature.
What unit is used for temperature when discussing gas properties and laws?
Kelvin
Which gas law describes the relationship between pressure and volume at constant temperature? Write the equation.
Boyle's Law
P1V1 = P2V2
A gas has a volume of 4.0 L at 2.0 atm. If it is compressed to 2.0 L at constant temperature, what is its new pressure?
4.0 atm
According to the Kinetic Molecular Theory, what happens to the kinetic energy of gas particles when temperature increases?
Average kinetic energy increases.
What happens to the air pressure inside a rigid, sealed container when its temperature increases?
Pressure increases.
Convert 25*C to K
25 + 273.15 = 298.15K
Which gas law describes the relationship between volume and temperature at constant pressure? Write the equation.
Charles' Law
V1 / T1 = V2 / T2
A gas occupies 3.0 L at 300 K. What volume will it occupy at 600 K if pressure remains constant?
6.0 L
What type of collisions occur between gas particles according to the Kinetic Molecular Theory?
Elastic collisions; total kinetic energy is conserved in collisions.
A soccer ball feels softer after sitting outside on a cold day. Explain what happens to the motion of the gas particles inside it.
Particles lose average kinetic energy and move more slowly, reducing the frequency and force of collisions. (Reducing pressure)
Convert 300K to *C
300K - 273.15 = 26.85 *C
Which gas law describes the relationship between pressure and temperature at constant volume? Write the equation.
Gay-Lussac's Law
P1 / T1 = P2 / T2
A gas has a pressure of 80 kPa at 200 K. What will its pressure be at 400 K if volume remains constant?
160 kPa
Explain why gas particles exert pressure on the walls of their container.
Gas particles collide with container walls and exert force, creating pressure.
Identify the relationship between pressure and volume when temperature remains constant.
Indirect (inverse) relationship.
A gas has a temperature of 127 *C. What is the temperature in Kelvin?
127 *C + 273.15 = 400.15 K
Which gas law equation should you use when pressure, volume, and temperature all change between two conditions? Write the equation.
Combined Gas Law
P1V1 / T1 = P2V2 / T2
A gas begins at 100 kPa, 4.0 L, and 300 K. Its volume changes to 2.0 L and its temperature changes to 600 K. What is its final pressure?
400 kPa
A gas is compressed into a smaller space without changing its temperature. Using the Kinetic Molecular Theory, explain why its pressure increases.
The same amount of gas occupies less space, so particles hit the walls more frequently, increasing pressure.
A sealed, rigid container of gas is heated. Describe the changes in particle speed, collision force or frequency, and pressure.
Particles move faster, collisions with the walls become more frequent and typically more forceful, and pressure increases.
A gas is at 350K. Convert the temperature to Celsius and explain why Kelvin must be used in gas law equations.
350K - 273.15 = 76.85 *C
Kelvin is an SI unit, has no negative values, and reflects particle energy
Which gas law relates pressure, volume, moles, and temperature in one equation? Write the equation and gas constant number.
Ideal Gas Law
PV = nRT
R = 0.0821
A gas sample contains 1.5 moles at 300 K and 2.0 atm. Calculate its volume.
18.5 L