Limiting Reactants

Question 1

What is a limiting reactant

Answer 1

A reaction stops when all the particles of one of the reactants are used up. In a reaction involving two reactants.

Question 2

What are proportional in a limited reaction

Answer 2

Total Product Formed and Amount of Limiting Reactant used

Question 3

What do you do to find the mass of a product?

Answer 3

1. Write out the balanced equation.
2. Work out the relative formula masses of the limiting reactant and the product you want to find the mass of.
3. Work out how many moles there are of the limiting reactant.
4. Use the balanced equation to work out how many moles there’ll be of the product.
5. Use the number of moles, along with the relative formula mass of the product to calculate the mass.

Question 4

What mass of calcium chloride(CaCl₂) is produces when 3.7g of calcium hydroxide (Ca(OH)₂) reacts with excess of hydrochloric acid.

Answer 4

Balanced Equation:
Ca(OH)₂ + HCL -> CaCL₂ + 2H₂0

Limiting Reactant:
Ca(OH)₂

Product you want:
CaCl₂

Calculate the relative mass of each:
CaCl₂ = 40 + (35.5 x 2) = 111
Ca(OH)₂ = 40 + 2(16 + 1) = 74

Calculate the number of moles of Ca(OH)₂:
3.7 / 74 = 0.05mol

Calculate the mass of product:
0.05 x 111 = 5.55