Limiting reactants

limiting reactant

only specific amount given and is used up to stop reaction

Aim

calculate quantity of reactant and product

Safety

HCl is irritant

• use a pipette

• don’t spill on skin

Mg is highly flammable

• keep away from open fire

Hydrogen is explosive

• don’t make more that a boiling tube

Method

1. Half fill a test tube with hydrochloric acid and place in a test tube rack

2. Add 1cm of magnesium ribbon into test tube and quickly cover with a boiling tube, this traps hydrogen

3. Remove boiling tube and keep opening downwards to stop hydrogen escaping

4. Light a wooden splint and place under tube to hear a squeaky pop indicating presence of hydrogen

Conclusion

1. Reaction stopped when Mg dissolved- limiting reactant

2. Hydrogen gas given out- finishing product seems less