1.         Zinc and sulfur react to form zinc sulfide according to the following eqn.

8 Zn(s)   +  S8(s)   –à   8 ZnS

  1. If 2.00 mol of Zn are heated with 1.00 mol of S8, identify the limiting reagent.
  2. How many moles of excess reactant remain
  3. How many moles of the product are formed?

2.         Carbon reacts with steam, H2O, at high temp. to produce hydrogen and carbon monoxide.

  1. If 2.40 mol of carbon are exposed to 3.10 mol of steam, identify the limiting reactant.
  2. How many moles of each product are formed?
  3. What mass of each product is formed?

3.         Use the following eqn for the oxidation of Al in the following problems:

4 Al   +  3O2 -à  2Al2O3

  1. Which reactant is the limiting if 0.32 mol Al and 0.26 mol O2 are available?
  2. How many moles of Al2O3 are formed from the reaction of 6.28 mol of O2 and 9.15 mol of Al?
  3. If 3.17g of Al and 2.55 g of O2 are available, which reactant is limiting?

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4.         Nickel replaces silver from silver nitrate in solution according to the following equation:

2AgNO3 +  Ni   –à  2Ag  +  Ni(NO3)2

a.         If you have 22.9g of Ni and 112 g of AgNO3, which reactant is in excess?

  1. What mass of Ni(II)nitrate would be produced given the above quantities?

5.         Calculate the % yield of each of the following cases:

  1. Theoretical yield is 50.0g of product.  Actual yield is 41.9g.
  1. Theoretical yield is 290kg of product.  Actual yield is 20,000g.

6.         Tungsten (W) can be produced from its oxide by reacting the oxide with hydrogen at a high temperature according to the following equation:

WO3 +  3H2 –à  W   +   3H2O

a.         What is the %yield if 56.9g of WO3 yields 41.4g of tungsten?

  1. How many moles of tungsten will be produced from 3.72g of WO3 if the yield is 92.0%
  1. A chemist carries out this reaction and obtains 11.4g of tungsten.  If the % yield is 89.4% what mass of WO3 was used?

7.         Nitrogen dioxide, NO2, can be converted to dinitirogen pentoxide, N2O5, by reacting it with ozone,O3.  The reaction of NO2 takes place according to the following equation:

2NO2 +  O3 –à   N2O5 +   O2

  1. Calculate %yield for a reaction in which 0.38g NO2 reacts and 0.36g of N2O5 recovered?
  1. What mass of N2O5 will result from the reaction of 6.0mol of NO2 if there is a 61.1% yield in the reaction?

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