3 Step Stoichiometry
Part A Review: For the following chemical equations, write the possible mole ratios.
- 2 CO + O2 → 2 CO2
2CO2CO1 O2
1 O22 CO22 CO2
- Al2(CO3)3 → Al2O3 + 3 CO2
1Al2(CO3)31Al2(CO3)31 Al2O3
1 Al2O33 CO23 CO2
- 2 CO + O2 → 2 CO2
2CO2CO1 O2
1 O22 CO22 CO2
Part B Review: Using arrows to map your work solve the following 1-step and 2-step stoichiometry problems.
- How many moles of CO are needed to react completely with 7 moles of O2?
2CO + O2 → 2 CO2
7 moles CO x2 moles O2=3.5 moles O2
2 moles CO
- How many moles of carbon dioxide, CO2, can be formed by the decomposition of 5 moles of aluminum carbonate, Al2(CO3)3?
Al2(CO3)3 → Al2O3 + 3 CO2
5 moles Al2(CO3)3 x3 moles CO2=15 moles CO2
1 moles Al2(CO3)3
- How many grams of carbon monoxide, CO, are needed to react completely with 3 moles of oxygen gas, O2?
2 CO + O2 → 2 CO2
3 moles O2x2 moles CO=6 moles CO
1 moles O2
6 moles CO x 28.01 g =168.06 g
1 mole CO
Part C: Using arrows to map your work solve the following 3-step stoichiometry problems.
- How many grams of O2are required to burn 10 grams of ethane gas, C2H6?
2 C2H6 + 7 O2 → 4 CO2 + 6 H2O
10 g x 1 moles C2H6=0.3324 molesC2H6
30.08 g
0.3324 moles C2H6x7 moles O2=1.1636 moles O2
2moles C2H6
1.1636 moles O2x 32 g =37.23 g
1 moles O2
- How many grams of O2 are produced by the decomposition of 10 grams of potassium chlorate, KClO3?
2 KClO3 → 2 KCl + 3 O2
10 g x 1 moles KClO3=0.081599 molesKClO3
122.55 g
0.081599 molesKClO3x3 moles O2=0.122399 moles O2
2 molesKClO3
0.122399 moles O2x 32 g =3.9167 g
1 moles O2
- The chemist begins with 46 grams of Na. How many grams of Cl2 are needed?
2 Na + Cl2 → 2 NaCl
46 g x 1 mole Na=2.0008 molesNa
22.99g
2.0008 molesNax1 moles Cl2=1.0004 moles Cl2
2 molesNa
1.0004 moles Cl2x 70.9 g =70.93g
1 moles Cl2
- How many grams of H2O can be prepared from 5 moles of H2 at standard conditions?
2 H2 + O2 → 2 H2O
5 moles H2x2 moles H2O=5 moles H2O
2 moles H2
5 moles H2Ox 18.0 g =90.1 g
1 moles H2O