Percentage yield

• In a lot of reactions, not all reactants react to form products which can be due to several factors:
  • Other reactions take place simultaneously
  • The reaction does not go to?completion
  • Products are?lost?during separation and purification
• The?percentage yield?shows how much of a particular product you get from the reactants compared to the maximum theoretical amount that you can get:

• The?actual yield?is the number of moles or mass of product obtained?experimentally
• The?theoretical?yield?is the number of moles or mass obtained by a reacting mass calculation

Answer:

Step 1:?The symbol equation is:

Zn (s) ???+ ???CuSO₄?(aq) ????→ ????ZnSO₄?(aq) ???+ Cu (s)

Step 2:?Calculate the amount of zinc reacted in moles

Step 3:?Calculate the maximum amount of copper that could be formed from the molar ratio:

Since the ratio of Zn(s) to Cu(s) is 1:1 a maximum of 0.10 moles can be produced

Step 4:?Calculate the maximum mass of copper that could be formed (theoretical yield)

mass =?? mol? x??M

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? =?? 0.10 mol x 63.55 g mol^-1

? ? ? ? ? ? ? ? ? ? ?=?? 6.4 g?(2 sig figs)Step 5:?Calculate the percentage yield of copper