1. practice
How many grams of H2O are produced by completely reacting 24 g of O2?
2 H2 + O2  2 H2O
convert to moles  convert to the desired molecule  convert to grams
O2 = g/mol ; H2O = g/mol
24 g O2
1 mol O2
2 mol H2O
g H2O
32 g O2
1 mol H2O
= 27 g
H2O

2. Another How many grams of H2 are needed to form 34 g of H2O?
2 H2 + O2  2 H2O
convert to moles  convert to the desired molecule  convert to grams
H2 = g/mol ; H2O = g/mol
34 g H2O
1 mol H2O
2 mol H2
2.016 g H2
g H2O
2 mol H2O
1 mol H2
= 3.8 g H2

3. Balance the equation 1st, then do the problem
Na + Cl2  NaCl
How many grams of chlorine are needed to react with 37 g of Na? 2 2
37 g Na
1 mol Na
1 mol Cl2
70.90 g Cl2
22.99 g Na
2 mol Na
=57 g Cl2

4. More
CH4 + O2  H2O + CO2
How many grams of CH4 are needed to make 120 g of H2O? 2 2
120 g H2O
1 mol H2O
1 mol CH4
g CH4
g H2O
2 mol H2O
= 53 g CH4

5. Still Going
How many grams of H2CO3 are produced by completely reacting 24 g of CO2?
H2O + CO2  H2CO3
24 g CO2
1 mol CO2
1 mol H2CO3
g H2CO3
44.01 g CO2
= 34 g
H2CO3

6. Finally How many grams of AlCl3 are produced form 34 g of CuCl2?
Al + CuCl2  AlCl3 + Cu
34 g CuCl2
1 mol CuCl2
2 mol AlCl3
g AlCl3
g CuCl2
3 mol CuCl2
1 mol AlCl3
= 22 g
AlCl3

7. Homework HNO3 + Sc → Sc(NO3)3 + H2
How many grams of scandium III nitrate will be produced from 28.2 g of nitric acid?