STOICH SHOWDOWN

Mole Math

100

What is 1 mole equal to in particles?

6.022 x 10^{23 particles}

200

Convert 0.5 moles of H₂O to grams

9.0g (0.5mol x 18g/mol)

300

How many moles are in 36g of H₂O

2 moles (36/18)

400

How many molecules are in 2 moles of CO₂

1.204 x 10²⁴ molecules

500

Convert 22.4L of O₂ at STP to moles

1 mole

BCA

100

What does BCA stand for?

Before,Change,After

200

Complete a BCA for: H₂ + O₂ → H₂O (1 mol H₂, 1 mol O₂)

H₂ is limiting; makes 1 mol H₂O

300

Why are limiting reactants important in BCA tables?

They determine how much product is made

400

What’s left over if 4 mol H₂ reacts with 2 mol O₂?

0 mol H₂ left; 1 mol O₂ left

500

Complex BCA: N₂ + 3H₂ → 2NH₃ (3 mol N₂, 9 mol H₂)

All used up, makes 6 mol NH₃

Theoretical vs. Actual

100

Define theoretical yield.

Max product calculated using stoichiometry

200

What is actual yield?

The amount actually produced in lab

300

% yield = (40g ÷ 50g) × 100

80%

400

Why is actual yield < theoretical yield?

Losses from spills, side reactions, incomplete reactions

500

If 3 mol of A should make 6 mol B, but only 5 mol B is made, what’s % yield?

83.3%

Balancing & Ratios

100

Balance: H₂ + O₂ → H₂O

2H₂ + O₂ → 2H₂O

200

Balance: Al + O₂ → Al₂O₃

4Al + 3O₂ → 2Al₂O₃

300

Mole ratio in: N₂ + 3H₂ → 2NH₃

1:3:2

400

Ratio in: 4Fe + 3O₂ → 2Fe₂O₃

4:3:2

500

Balance: C₃H₈ + O₂ → CO₂ + H₂O

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Limiting Reactants

100

What is a limiting reactant?

The reactant that runs out first

200

2 mol A + 3 mol B → AB₃. What’s the limiting reactant?

A

300

If 5g of H₂ and 10g of O₂ react, which is limiting?

H₂ (less product made)

400

Use LR to find product: 2 mol N₂, 3 mol H₂ → NH₃

H₂ limits → 2 mol NH₃

500

6 mol HCl + 2 mol Al → AlCl₃ + H₂. LR?

HCl is limiting