Real vs Ideal Gases
According to KMT, increasing temperature causes this average property of gas particles to increase.
What is kinetic energy?
This equation relates pressure, volume, moles, temperature, and a constant.
What is the Ideal Gas Law?
P₁V₁ = P₂V₂ is known as this law.
What is Boyle's Law?
The phase change from liquid to gas.
What is vaporization?
A gas in a rigid container is heated. Using KMT, explain why pressure increases.
Gas particles move faster and collide with the container walls more frequently and with greater force.
In PV = nRT, this variable represents the amount of gas.
What is moles (n)?
If temperature doubles (in Kelvin) while pressure remains constant, volume will do this.
Double
Energy is absorbed or released during melting?
Absorbed
Real gases deviate most from ideal behavior under these conditions.
What are high pressure and low temperature?
A gas has 2.0 moles, is in a 10.0 L container at 300 K. This is what you do first to find pressure.
Substitute into PV = nRT and solve for P.
A gas occupies 2.0 L at 300 K. What volume will it occupy at 450 K if pressure remains constant?
3.0 L
A substance exists as both liquid and vapor in a sealed container. This condition is called:
What is phase equilibrium?
Real gases deviate most from ideal behavior because of these two factors.
What are intermolecular forces and particle volume?
Two gases are at the same temperature. Gas A has particles twice as massive as Gas B. Which gas has the greater average kinetic energy?
Neither. They have the same average kinetic energy because average kinetic energy depends only on temperature.
A 5.0 L container holds 0.50 mol of gas at 27°C. Find the pressure in atm.
2.46
27°C = 300 K
P(5.0) = (0.50)(0.0821)(300)
P(5.0) = 12.315
A gas has a volume of 6.0 L at 300 K and 1.0 atm. It is compressed to 3.0 L and heated to 600 K. What is the final pressure?
4.0 atm
(Using Combined Gas Law:
P₂ = P₁(V₁/V₂)(T₂/T₁)
= 1.0 × (6/3) × (600/300)
= 4.0 atm)
A substance is changing from a liquid to a gas, but the temperature stays constant even though heat is still being added. What is this process called?
What is boiling (or vaporization at the boiling point)?
A gas is cooled and compressed into a very small container. Explain why it no longer behaves ideally.
Low temp means slow rates of movement, therefore intermolecular forces are important. The volume of particles is important at high pressure. As the gas deviates from the KMT assumptions, it does not behave ideally.
A gas sample is heated from 300 K to 600 K in a rigid container. The pressure doubles. Explain why this happens using kinetic molecular theory, not just a formula.
As temperature rises the energy of the particles in a gas increases, so the particles move faster. The more the particles collide with the walls of the rigid container the faster they do it, because volume does not change. The pressure rises with these frequent and intense crashes. The increase in temperature causes the average kinetic energy to double, causing the pressure to double.
A 1.00 L container holds 0.80 moles of gas at 310 K. Using the ideal gas law, calculate the pressure in atm.(R=0.0821)
20.36
A gas occupies 10.0 L at STP. It is heated to 546 K and compressed until its pressure becomes 2.0 atm. What is its new volume?
What is 10.0 L?
(1.0 × 10.0) / 273 = (2.0 × V₂) / 546
(1.0 × 10.0 × 546) = (2.0 × V₂ × 273)
5460 = 546 × V₂
A solid is heated continuously at its melting point. Even though heat is being added, the temperature does not change. Explain why.
The additional energy is not being added to the temperature. Rather, it is being used to break apart intermolecular forces that bind the solid together. This energy is called latent heat of fusion and the particles separate into a liquid rather than get faster.