Mole Math
What is 1 mole equal to in particles?
6.022 x 1023 particles
What does BCA stand for?
Before,Change,After
Define theoretical yield.
Max product calculated using stoichiometry
Balance: H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
What is a limiting reactant?
The reactant that runs out first
Convert 0.5 moles of H2O to grams
9.0g (0.5mol x 18g/mol)
Complete a BCA for: H₂ + O₂ → H₂O (1 mol H₂, 1 mol O₂)
H₂ is limiting; makes 1 mol H₂O
What is actual yield?
The amount actually produced in lab
Balance: Al + O₂ → Al₂O₃
4Al + 3O₂ → 2Al₂O₃
2 mol A + 3 mol B → AB₃. What’s the limiting reactant?
A
2 moles (36/18)
Why are limiting reactants important in BCA tables?
They determine how much product is made
% yield = (40g ÷ 50g) × 100
80%
Mole ratio in: N₂ + 3H₂ → 2NH₃
1:3:2
If 5g of H₂ and 10g of O₂ react, which is limiting?
H₂ (less product made)
How many molecules are in 2 moles of CO2
1.204 x 1024 molecules
What’s left over if 4 mol H₂ reacts with 2 mol O₂?
0 mol H₂ left; 1 mol O₂ left
Why is actual yield < theoretical yield?
Losses from spills, side reactions, incomplete reactions
Ratio in: 4Fe + 3O₂ → 2Fe₂O₃
4:3:2
Use LR to find product: 2 mol N₂, 3 mol H₂ → NH₃
H₂ limits → 2 mol NH₃
Convert 22.4L of O2 at STP to moles
1 mole
Complex BCA: N₂ + 3H₂ → 2NH₃ (3 mol N₂, 9 mol H₂)
All used up, makes 6 mol NH₃
If 3 mol of A should make 6 mol B, but only 5 mol B is made, what’s % yield?
83.3%
Balance: C₃H₈ + O₂ → CO₂ + H₂O
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
6 mol HCl + 2 mol Al → AlCl₃ + H₂. LR?
HCl is limiting