Gas Laws
Which gas law states that pressure and volume are inversely related when temperature is constant?
Boyle’s Law
At the same temperature and pressure, equal volumes of gases contain equal what?
Number of Molecules
What is the limiting reagent? (Define the term)
The reactant that gets used up first and stops the reaction. (The reagent with the lowest stoichiometric quantity.)
Balance this equation:
H2+O2→H2O
2H2+O2→2H2O
What unit is used to measure the amount of substance in chemistry?
Mole
Which gas law states that volume increases as temperature increases, as long as pressure stays constant?
Charles’ Law
At STP, what volume does 1 mole of any ideal gas occupy?
22.4 L
In a chemical reaction, which reactant determines the maximum amount of product formed?
The limiting reagent
Balance this equation:
N2+H2→NH3
N2+3H2→2NH3
How many particles are in 1 mole of a substance?
6.02×1023 particles
A gas has a volume of 2.0 L at 300 K. If the temperature increases to 450 K at constant pressure, what is the new volume?
3.0 L
How many moles are in 48 L of oxygen gas at RTP?
2.0 mol
Remember at RTP Molar Volume is equal to 24 L
For the reaction
2H2+O2→2H2O
If you have 4 mol H2 and 1 mol O2, which reactant is limiting?
O2 is limiting
Because 1 mol O2 needs 2 mol H2, so only 2 mol H2 can react
Balance this equation:
Fe+O2→Fe2O3
4Fe+3O2→2Fe2O3
How many moles are in 36 g of water (H2O)
2.0 mol
A gas occupies 5.0 L at 100 kPa. If the pressure changes to 250 kPa at constant temperature, what is the new volume?
2.0 L
According to the equation:
2H2+O2→2H2O
If 4.0 mol of H2 reacts completely, how many moles of H2O are formed?
4.0 Mol
For the reaction
N2+3H2→2NH3
If you have 2 mol N2 and 4 mol H2, which is the limiting reagent and how much of it is needed?
H2 is the limiting reagent
2 mol N2 would require 6 mol H2, but only 4 mol are available
Balance this equation:
C3H8+O2→CO2+H2O
C3H8+5O2→3CO2+4H2O
How many molecules are in 0.5 mol of CO2
3.01×1023 molecules
0.5×6.02×1023=3.01×1023
A gas has a volume of 3.5 L at 27°C. It is heated to 127°C at constant pressure. What is the new volume?
4.7 L
NOTE: Convert to Kelvin first:
27°C = 300 K, 127°C = 400 K
According to the equation
N2+3H2→2NH3
What volume of ammonia is produced at STP from 33.6 L of hydrogen gas, assuming nitrogen is in excess?
22.4 L NH3
Ratio: 3 volumes H2 : 2 volumes NH3
For the reaction
2Al+3Cl2→2AlCl3
If you have 4 mol Al and 5 mol Cl2, which reactant is limiting, and how many moles of AlCl3 can form?
Cl2 is limiting, and 3.33 mol AlCl3 can form
Balance this equation:
Al+HCl→AlCl3+H2
2Al+6HCl→2AlCl3+3H2
What mass of NaCl is present in 2.5 mol of sodium chloride?
Note the molar mass off NaCl= 58.5 g/mol
146.25 g
2.5 mol×58.5 g/mol =146.25 g