Limiting Reactant

+ ?

2B + S ?

+

+

2B + S B2S

+

2B + 1S 1B2S

Bread (B) and Salami (S) react in a2 to 1 (2:1) ratio to produce

sandwich (B2S)

+

6B + 2S ?

+

+(leftover)

6B + 2S

+

2B2S

6B + 2S

+

2B2S

The amount of salami limits the amount of sandwichesthat can be produced

what reaction could this be?

2H2 + 1 O2 2H2O

?

what happensif there is an excess amountof hydrogen?

?

?

?

5H2 + 1 O2 2H2O+ 3H2

?

excess H2 + 1 O2 2H2O

Limiting Reactant

The limiting reactant is the reactant you run out of first.

The excess reactant is the one you have left over.

The limiting reactant determines how much product you can make

Calculating Limiting Reactant Do two stoichiometry problems. The one that makes the least product is

the limiting reagent.

If 10.6 g of copper reacts with 3.83 g S. How many grams of product will be formed?

2Cu + S ® Cu2S

10.6 g Cu 63.55g Cu 1 mol Cu

2 mol Cu 1 mol Cu2S

1 mol Cu2S159.16 g Cu2S

= 13.3 g Cu2S

3.83 g S 32.06g S 1 mol S

1 mol S 1 mol Cu2S

1 mol Cu2S159.16 g Cu2S

= 19.0 g Cu2S

= 13.3 g Cu2S

Cu is Limiting Reagent

Your turnMg + 2HCl ® MgCl2 + H2

If 10.1 g of magnesium and 2.87 g of HCl gas are reacted, how many grams of hydrogen gas will be produced?

What is the excess reactant?

Your Turn II 2Al + 3CuSO4 ® Al2(SO4)3 + 3Cu If 10.3 g of aluminum are reacted with

51.7 g of CuSO4 how much copper will be produced?

What is the excess reagent?