SCH4C Stoichiometry Design Lab Name

SCH4C Stoichiometry Design Lab Name: Strontium and Copper (II)

Your Task: in this lab, you will start with a known mass of strontium chloride hexahydrate and a known mass of copper (II) sulfate pentahydrate. You will calculate the moles of each substance and then determine the theoretical mass of the precipitate that should be formed. Once the procedure is complete, you will mass the actual precipitate formed. The difference between the actual yield and the calculated (theoretical) yield can then be used to determine the percent yield of your product.

Purpose:  To write and balance an equation with states included  To calculate the theoretical yield of a reaction  To mass the actual mass of a reaction  To compare the actual mass to the theoretical mass and determine percent yield.

Materials:  Eye protection  2-250 mL beakers  Scoopula  Filter paper  2.00 g strontium chloride hexahydrate  Funnel  2.00 g copper (II) sulfate pentahydrate  Ring  75 mL water  Ring stand  Graduated cylinder  Digital scale   Procedure: 1. Mass 2.000 g strontium chloride hexahydrate into a 250 mL beaker 2. Mass 2.000 g copper (II) sulfate pentahydrate into a 250 mL beaker 3. Measure 35 mL water using a graduated cylinder and pour into copper (II) sulfate pentahydrate. Stir. 4. Measure 40 mL water using a graduated cylinder and pour into strontium chloride hexahydrate. Stir. 5. Combine the two aqueous solutions into one beaker. 6. Mass the filter paper. Fold a filter paper as instructed and place it into the funnel. Set the ring stand, ring with funnel over the empty beaker. 7. Filter the precipitate. Make sure to rinse empty beaker into filter paper to capture all PPT. Let the precipitate dry. Clean up equipment and station. 8. Mass the dry precipitate and filter paper.   Observations:  Table 1: Qualitative Observations  Copper (II)  Strontium  Mixture of  Precipitate  Dry PPT Sulfate Chloride both (s) on filter pentahydr hexahydrat solutions paper ate (s) e (s)          SCH4C Stoichiometry Design Lab Name: Strontium and Copper (II)

  Table 2: Quantitative Observations  Mass Copper  Mass  Mass of filter  Mass of filter (II) Sulfate Strontium paper (g) paper and dry pentahydrate Chloride ppt (g) (g) hexahydrate (g)           Volume of  Volume of Water (mL) Water (mL)       Balanced Equation:  Strontium chloride hexahydrate reacts with copper (II) sulfate pentahydrate to produce strontium sulfate as a precipitate. The other product is copper (II) chloride, which remains in solution.        Calculations:  1. Molar mass Copper II Sulfate pentahydrate    2. Moles Copper II Sulfate pentahydrate    3. Molar Mass Strontium Chloride hexahydrate     4. Moles Strontium Chloride hexahydrate    SCH4C Stoichiometry Design Lab Name: Strontium and Copper (II)

 Analysis: 5. Mole ratio (based on balanced equation) between Copper Sulfate and Strontium Chloride    6. Use mole ratio and one of the answers in 2 or 4 to determine the limiting reactant.    7. Mole ratio between limiting reactant and PPT (based on balanced equation)    8. Use mole ratio of limiting reactant and PPT with the moles determined in step 2 or 4.    9. Convert moles to grams using the molar mass of PPT. (This is theoretical yield, you calculated what you should get)    10. Mass of the PPT (This is your actual yield)    11. Percent yield = actual yield / theoretical yield x 100%        Discussion:  Copper II ions dissolve in solution generally appear as a pale blue colour. Why is the colour of the final reaction NOT a good indication of which reactant is the limiting reactant?     Is it possible to achieve more than 100% yield? Explain.   SCH4C Stoichiometry Design Lab Name: Strontium and Copper (II)

   What are some reasons why the theoretical yield is not the same as the actual yield?     Sources of Error:         INCLUDE: percentage error calculation.  % error =                   Expectations  E2. investigate chemical compounds and chemical reactions using appropriate techniques of quantitative analysis, and solve related problems; . E2.1 use appropriate terminology related to stoichiometry . E2.2 calculate the molar mass of simple compounds with the aid of the periodic table . E2.4 solve problems involving relationships between the following variables in a chemical reaction: quantity in moles, number of particles, atomic mass, concentration of solution, and volume of solution . E2.5 solve problems involving stoichiometric relationships in balanced chemical equations SCH4C Stoichiometry Design Lab Name: Strontium and Copper (II)

. E2.6 conduct an inquiry to determine the actual yield, theoretical yield, and percentage yieldof the products of a chemical reaction and suggest sources of experimental error   E3. demonstrate an understanding of the mole concept and its quantitative relationships in chemical reactions.

. E3.1 describe the relationships between Avogadro’s number, the mole concept, and the molar mass of any given substance

. E3.2 describe some possible sources of experimental error in an investigation of a chemical reaction, and explain how the errors would affect the percentage yield of products of the reaction

. E3.3 explain the relationships between the mole concept, the values of coefficients, the number of particles, and the mass of substances in balanced chemical equations

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