6. Chemical Reactions & Quantities

What is the percent yield for a reaction in which 22.1 g Cu is isolated by reacting 45.5 g Zn with 70.1 g CuSO₄?  

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

Ammonia, NH₃, reacts with hypochlorite ion, OCl^–, to produce hydrazine, N₂H₄. How many grams of hydrazine are produced from 115.0 g NH₃ if the reaction has a 81.5% yield?  

2 NH₃ + OCl^– → N₂H­₄ + Cl^– + H₂O

The reduction of iron (III) oxide creates the following reaction: 

Fe₂O₃ (s) + 3 H₂ (g) → 2 Fe (s) + 3 H₂O (g) 

If the above reaction only went to 75% completion, how many moles of Fe₂O₃ were require to produce 0.850 moles of Fe? 

The reaction of ethylene oxide with water to give ethylene glycol (automobile antifreeze) occurs in 96.0% actual yield. How many grams of ethylene glycol are formed by reaction of 35.0 g of ethylene oxide? (For ethylene oxide, MW = 44.0 amu; for ethylene glycol, MW = 62.0 amu.)

Consider the balanced chemical equation: A₂ + 2 B₂ → 2 AB₂. A reaction is performed with the initial amounts of A₂ and B₂ shown in part (a). The amount of product obtained is shown in part (b). Calculate the percent yield.

a. <IMAGE>

b. <IMAGE>