The Limiting Reactant Chemistry 11 Ms. McGrath

The Limiting Reactant The coefficients of a balanced chemical chemical equation gives the mole ratio of the reactants and products. This is emphasized by referring to the coefficients as stoichiometric coefficients. Reactants are said to be present in stoichiometric amounts.

The Limiting Reactant When chemical reactions occur, there is typically reactants left over. For example, in the following reaction, zinc is removed from zinc oxide. ZnO (s) + C (s) -> Zn (s) + CO (g) In a laboratory it is possible to obtain samples of zinc oxide and carbon in a 1:1 ratio.

The Limiting Reactant ZnO (s) + C (s) -> Zn (s) + CO (g) In an industrial setting, it would be impractical to spend time and money ensuring that zinc oxide and carbon are in proper stoichiometric ratios. It is also not necessary. Engineers add more carbon (in the form of charcoal) for the reaction to occur. All the zinc oxide reacts but carbon remains.

The Limiting Reactant Complete the thought lab on page 129.

The Limiting Reactant The reactant that is used up completely in a chemical reaction is called the limiting reactant. The limiting reactant runs out first and determines how much product is produced.

The Limiting Reactant The reactant that remains after a chemical reaction is called the excess reactant.

The Limiting Reactant Calculations When determining the limiting reactant you can find out how much product is produced by each reactant, if the other reactant is in excess. The reactant the produces the least amount of reactant is the limiting reactant.

The Limiting Reactant Calculations - Example Lithium nitrate reacts with water to form ammonia and lithium hydroxide, according to the following balanced equation: Li 3 N (s) + 3H 2 O (l) -> NH 3(g) + 3LiOH (aq) If 4.87 g of lithium nitrate reacts with 5.80 g of water, find the limiting reactant.