2. Limiting Reactant

3. + ? 2B + S ?

12. +

13. + 2B + S B 2 S

14. + 2B + 1S 1B 2 S Bread (B) and Salami (S) react in a 2 to 1 (2:1) ratio to produce sandwich (B 2 S)

15. + 6B + 2S ?

25. + + (leftover)

26. 6B + 2S + 2B 2 S

27. 6B + 2S + 2B 2 S The amount of salami limits the amount of sandwiches that can be produced

28. what reaction could this be?

62. 2H 2 + 1 O 2 2H 2 O

63. ? what happens if there is an excess amount of hydrogen?

93. ?

94. ?

95. ? 5H 2 + 1 O 2 2H 2 O+ 3H 2

96. ? excess H 2 + 1 O 2 2H 2 O

97. Limiting Reactant u The limiting reactant is the reactant you run out of first. u The excess reactant is the one you have left over. u The limiting reactant determines how much product you can make

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

99. u If 10.6 g of copper reacts with 3.83 g S. How many grams of product will be formed?  2Cu + S  Cu 2 S 10.6 g Cu 63.55g Cu 1 mol Cu 2 mol Cu 1 mol Cu 2 S 1 mol Cu 2 S 159.16 g Cu 2 S = 13.3 g Cu 2 S 3.83 g S 32.06g S 1 mol S 1 S 1 Cu 2 S 1 mol Cu 2 S 159.16 g Cu 2 S = 19.0 g Cu 2 S = 13.3 g Cu 2 S Cu is Limiting Reagent

100. Your turn Mg + 2HCl  MgCl 2 + H 2 u If 10.1 g of magnesium and 2.87 g of HCl gas are reacted, how many grams of hydrogen gas will be produced? u What is the excess reactant?

101. Your Turn II 2Al + 3CuSO 4  Al 2 (SO 4 ) 3 + 3Cu u If 10.3 g of aluminum are reacted with 51.7 g of CuSO 4 how much copper will be produced? u What is the excess reagent?