Honors Chemistry

Directions: Show all work for the following problems.

Calculating Molar Mass

  1. Determine the molar masses of these compounds.
  2. Ag2CO3
  1. Mg(HCO3)2
  1. BaCl2·2H2O
  1. One molecule of the antibiotic known as penicillin G has a mass of 5.342 x 10-21 grams. What is the molar mass of penicillin G?

Converting between Grams, Moles, and Molecules

  1. Superman comes from the planet Krypton. If you have 0.00789 g of the gaseous element krypton how many moles does this represent? How many atoms?
  1. How many moles are contained in 0.684 g MgCl2?
  1. How many molecules are in 2.50 kg NaCl?
  1. What is the mass of 5.00 moles of H2O?
  1. How many molecules are contained in 1.26 mol O2?
  1. How many molecules of hydrochloric acid HCl are there in 25.0 g of hydrochloric acid?

Percent Composition

  1. Calculate the mass percent of each element in lead II sulfide.
  1. Calculate the percentage of H2O in CoCl2·6H2O.

CoCl2·6H2O = 58.93 + 2(35.45) + 6(18.02) = 237.95 g/mol

  1. A 6.20 g sample of phosphorus was reacted with oxygen to form an oxide with a mass of 14.20 g. Calculate the percentage composition of the compound.
  1. Your doctor has diagnosed you as being anemic, that is, having too little iron in your blood. At the drugstore you find two iron-containing dietary supplements, one with iron II sulfate, FeSO4, and the other with iron II gluconate, Fe(C6H11O7)2. If you take 100. mg of each compound, which delivers more iron?

Chemical Reactions

Predict the molecule that would go in the space(s) for each chemical equation, then balance and classify the reaction

1.KBrO3 (s)KBr(s)+______

2.Mg(s)+______MgO(s)

3.Zn(s)+CuSO4 (aq)______+______

4.Zn(C2H3O2)2(aq)+Na3PO4(aq)______+______

5.Fe(s)+Na2CO3 (aq)______+______

6.NH3(g)______+______

7.C3H8(g)+O2(g)CO2 (g)+______

8.Na2SO4(aq)+KCl(aq)______+

______

9. Combustion of propane (C3H8)

  1. Bromine + potassium iodide 
  1. Magnesium + hydrochloric acid 
  1. Sodium hydroxide + acetic acid 
  1. Zinc + sulfuric acid 
  1. Heating magnesium carbonate
  1. Sodium + chlorine 
  1. Lead(II) nitrate + sodium iodide 
  1. Silver nitrate + sodium sulfide 
  1. Iodine + potassium chloride 
  1. Magnesium oxide + water 

Stoichiometry

1. If 120. g of sodium carbonate react with 105g of calcium hydroxide, how many grams of sodium hydroxide are formed? Na2CO3 + Ca(OH)2—> NaOH + CaCO3

2. When 80.0 g of calcium chloride react with 50.0g of silver nitrate, how many grams of silver chloride are produced? CaCl2 + AgNO3 —> Ca(NO3)2 + AgCl

3. How many grams of oxygen are produced by heating 400. g of potassium chlorate?

KClO3 —> KCl + O2

4. Calculate how many grams of water would be produced when you react 25.0g of each reactant.

H3PO4 + NaOH —> Na3PO4 + H2O

5. How many grams of calcium carbonate are required to prepare 50.0 g of calcium oxide? CaCO3 —> CaO + CO2

6. Calculate the mass of sulfur which would react with 0.576 mol of copper.

Cu + S8 —> Cu2S

7. Calculate the moles of silver formed by heating 10.0 g of silver oxide.

Ag2O —> Ag + O2

8. If 50.0 g of magnesium metal react with 30.0 g oxygen, what mass of magnesium oxide is formed? Mg + O2 —> MgO

Percent Yield

1) A student adds 200.0g of C7H6O3 to an excess of C4H6O3, this produces C9H8O4 and C2H4O2. Calculate the percent yield if 231 g of aspirin (C9H8O4) is produced in an experiment.

___C7H6O3+___C4H6O3___C9H8O4 +___C2H4O2

2) According to the following equation, Calculate the percentage yield if 550.0 g of toluene (C7H8)added to an excess of nitric acid (HNO3) provides 305 g of the p-nitrotoluene (C7H7NO2) product in a lab experiment.

___C7H8 +___HNO3___C7H7NO2 +___H2O

3 Aluminum reacts with an aqueous solution containing excess copper (II) sulfate. If 1.85 g Al reacts and the percentage yield of Cu is 56.6%, what mass of Cu is produced?

___Al +___CuSO4___Cu +___Al2(SO4)3

Energy