VolumeVolume Problems
N2 + 3H2 > 2NH3
What volume of hydrogen is necessary to react w/ five liters of nitrogen to produce ammonia?
So you are trying to find the volume of hydrogen. Before you start, know that 1 mole of a gas is equal to
22.4 L, that's the STP (standard temperature and pressure). So start out with the given (5L N2). Then go straight to the STP
which gives you one mole of N2. For every one mole of N2, there are 3 moles of H2. 1 mole H3 is equal to 22.4 L.
Now multiply it out!
Limiting Reagents
N2 + 3H2 > 2NH3
How many grams of NH3 can be produced from the reaction of 28 g of N2 and 25 g of H2?
For this problem, you do 2 seperate dimensional analysis problems: one starting with the 28 g and one
starting with the 25 g. You go from 28 grams and do a massmass problem to find grams of NH3. After you find that answer,
you do the same with the 25 grams. You get two answers, correct? You take the lowest one because you it is the one that will
run out the fastest, aka, the limiting reagent.
Practice problems:
VolumeVolume
1. 2H2O > 2H2 + O2 If 30 mL of hydrogen are produced in the above reaction, how many liters of
Carbon dioxide are produced?
2. 2CO + O2 > 2CO2 How many liters of CO2 are produced if 75 liters of carbon monoxide are burned in oxygen?
Answers:
1. 60
2. 75
Limiting Reagent
1. Mg + 2HCl > MgCl2 + H2 What volume of hydrogen at STP is produced from the raction of 50 g of Mg and the
equivalent of 75 g of HCl?
2. 3AgNO3 + Na3PO4 > Ag3PO4 + 3NaNO3 Silver nitrate and sodium phosphate are reacted in equal amounts of
200 g each. How many grams of silver phosphate are produced?
Answers
1. 23.01 L HCl
2. 56.6 g AgNO3
