Gas Laws and Calculations
What volume does 3.00 moles of an ideal gas occupy at STP?
67.2 L
What does temperature represent in a gas system?
The average kinetic energy of gas molecules.
How many liters of NH3 gas are produced from 2.0 L of N2 gas at STP?
(N2 + 3H2 -> 2NH3)
4.0 L
What is the primary difference between diffusion and effusion?
Diffusion is the spread of particles in space; effusion is through a small hole.
Why do weather balloons expand as they rise?
Lower atmospheric pressure allows gas expansion.
If the pressure of a gas is doubled while temperature remains constant, what happens to its volume>
It is halved (Boyle's Law)
Why does the pressure of a gas increase when its temperature rises at constant volume?
Molecules move faster and collide more frequently with container walls.
A reaction uses 10.0 L of O2 gas at STP. How many liters of CO2 gas are produced?
(2C2H2 + 5O2 -> 4CO2 + 2H2O)
8.0 L
Which gas effuses faster, HCl or NH3?
NH3
What causes acid rain?
Sulfur dioxide (SO2) and nitrogen oxides (NOx) realeased during combustion of coal and other fuels react with atmospheric hydroxide (OH) to form sulfuric acid (H2SO4) and nitric acid (HNO3). These acids dissolve and dissociate in water to form acid rain.
A gas has a volume of 5.0 L at 300K and 1.2 atm. What will its volume be at 400K and 1.2 atm?
6.67 L
Rank the following gases by increasing average molecular speed at 25°C: O2, N2, He.
O2 < N2 < He
Given 5.0 L of chlorine gas and 6.0 L of NH3, how much N2 gas is produced? (2NH3 + 3Cl2 -> N2 + 6HCl)
2.0 L
If helium gas effuses at 6.0 mol/hr, how fast does argon effuse?
1.90 mol/hr
What is the chemical equation for ozone formation in the atmosphere?
NOx + UV (light) ->NO + O;
O + O2 -> O3
How many moles of gas are un a 10.0L container at 2.00 atm and 273 K?
0.89 moles
Why do lighter gas molecules move faster than heavier ones at the same temperature?
According to the kinetic molecular theory, all gases have the same average kinetic energy at a given temperature, so lighter molecules must move faster to have the same energy as heavier ones.
What mass of CO2 is produced from burning 44.8 L of CH4 at 298K and 1.5 atm?
(CH4 + 2O2 -> CO2 + 2H2O; R = 0.0821 L.atm/mol.K)
106 g
A gas effuses at half the rate of oxygen gas. What is its molar mass?
64 g/mol
How does scuba diving relate to gas laws?
Boyle’s Law explains decompression sickness (the bends), where dissolved gases in the bloodstream form bubbles if a diver ascends too quickly. As pressure drops when the diver approaches sea level, tiny bubbles can expand in volume and cause tissue and nerve damage.
A weather balloon at 1.00 atm and 20°C expands from 30.0 L to 75.0 L. What is the final pressure if temperature drops to -10 °C?
0.29 atm
Why is it called the Ideal Gas Law?
Because it assumes gases behave ideally, which is an approximation of real gases.
How many liters of N2 gas can be made from 13 L of Cl2 and 10 L of NH3 at 310K and 1.2 atm?
(2NH3 + 3Cl2 -> N2 + 6HCl; R = 0.0821 L.atm/mol.K)
4.95 L
Compare the rates of diffusion of CO2 and OCO2 diffuses about 1.05 times faster than O3. at the same temperature.
CO2 diffuses about 1.05 times faster than O3.
Why do car tires inflate more in hot weather?
According to Gay-Lussac’s Law, increasing temperature raises pressure when volume is constant, causing tires to expand.