Conversion Factors
How do you convert grams to moles?
divide by molar mass
How many moles of H2 will be produced from 20 moles of Pb?
Pb + 2HCl => PbCl2 + H2
20 moles
20 x (1/1) = 20
What is a reactant that is completely used up during a reaction?
limiting reaction
How do you convert moles to number of particles?
multiply by 6.02x10^23
How many moles of HNO3 will be produced from 5 mol of N2O5 are reacted?
N2O5 + H2O => 2HNO3
10 moles
5 x (2/1) = 10
A compound that reacts with more than the needed amount in a chemical reaction is called ____________.
Excess reactant
How do you convert moles of MgCl2 to moles AlCl3?
3MgCl2 + Al2(SO4)3 => 3MgSO4 + 2AlCl3
multiply by 2/3
How many moles of CO2 will be produced from 8 mol ZnO?
C + 2ZnO => 2Zn + CO2
4 moles
8 x (1/2) = 4
When 4 moles of C are reacted with 13 moles O2, what is the limiting reagent?
2C + O2 => 2CO
Carbon
4 x 2/2 = 4
13 x 2/1 = 26
How do you convert moles of tin to moles of hydrogen gas?
Sn + 2NaOH => Na2SnO2 + H2
multiply by 1/1
How many moles of PBr3 will be produced from 3 mol Br2?
2P + 3Br2 => 2PBr3
2 moles
3 x (2/3) = 2
Which reactant is in excess when 20g of HCl are reacted with 20g of Li?
2HCl + 2Li => 2LiCl + H2
Li
20/7 x 1/1 excess
20/36 x 1/1 limit
How do you convert moles of NaOH to moles of hydrogen gas?
Sn + 2NaOH => Na2SnO2 + H2
multiply by 1/2
How many moles of NH3 will be produced from 15 mol N2?
N2 + 3H2 => 2NH3
30 moles
15 x (2/1) = 30
If 0.74g of Fe reacts with 0.38g of O2, which one is the limiting reactant?
3Fe + 2O2 => Fe3O4
Fe is the limit
0.74/56 x 1/3 = 0.004 limit
0.38/32 x 1/2 = 0.006 excess