Limiting Reactants | GCSE Chemistry Practice
In a chemical reaction, the limiting reactant is the one that is used up first.
If 2 moles of A react with 5 moles of B (1:1 ratio), which is limiting?
What is Limiting Reactants | Practice?
"The reactant that is completely consumed in a chemical reaction and determines the amount of product formed."
Calculate the relative formula mass (Mr) of H2O. (H=1, O=16)
Calculate the mass of 0.25 moles of Calcium Carbonate (CaCO3). (Mr=100)
How many moles are in 36g of water? (Mr of H2O = 18)
Which formula is used to calculate the number of moles?
The Finish Line
The reaction stops as soon as one reactant is completely consumed.
The other reactant is said to be "in excess".
The amount of product formed is directly proportional to the amount of limiting reactant.
Calculating the limiting reactant requires using the molar ratio from the balanced equation.
Logic Check: Even if you have "more grams" of a substance, it might still be limiting if its $M_r$ is very high!
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