The Heat is On With Zinc and Copper (II) Sulfate

When zinc granules are added to a solution of copper (II) sulfate, a number of changes can be seen. The copper ion is responsible for the blue color of the copper (II) sulfate solution. Metallic copper will appear as a brownish solid.

In this procedure, the amount of copper in the copper (II) sulfate solution never changes.

Place 2.50 ml of copper (II) sulfate solution into a 50-ml beaker. Place the thermometer in the solution and record the temperature of the solution. Weigh out the number of grams of zinc (0.100g, 0.200g, 0.400g and 0.800g). Stir the zinc into the solution with the thermometer and record the highest temperature reached during this reaction. Construct a graph by plotting the amount of zinc on the x axis and the change of temperature on the y axis for each set of data.

Each pair of students will have the same set of data. However, each student will have has own lab report.

Prelab Assignment

Statement of the Problem paragraph

Procedure

Data Chart (must be done with a straight edge)

Lab Report (Formal Lab Report – Major Grade)

Title Page

I. Statement of the Problem (paragraph)

A. Identify

1. MSDS information - copper (II) sulfate solution

2. MSDS information - Zn

3. endothermic and exothermic reactions (where will heat be located in an equation for each of these reactions)

4. limiting and excess reagents

5. present the balanced chemical equation for the reaction between zinc and copper (II) sulfate

B. End the paragraph with the statement of the problem - consider what is being measured, what is changing and how is it changing, and what remains constant

II. Procedure (paragraph)

III. Data

A. Data Chart

Mass of zinc (g)Temp (oC)Temp (oC) Temp Change

(initial)(final) (oC)

0.100

0.200

0.400

0.800

B.Graph

1. full page

2. each axis labeled and unit give

3. title must reflect what is graphed

4. draw the best possible curve

IV. Conclusion

In paragraph form answer these six questions.

1. Is this an endothermic or exothermic reaction? Support your response.

2. What type of reaction has occurred (combination, decomposition, etc.)? Explain you choice.

3. Which substance is the limiting reagent in the mixture of 0.100 g of zinc plus 2.50 ml of copper (II) sulfate solution? Support your response using the information from the graph and from qualitative observations.

4. Which substance is the limiting reagent in the mixture of 0.8 g of zinc and 2.50 ml of copper (II) sulfate solution? Support your response using the information from the graph and from qualitative observations.

5. Explain the curve on the graph. Why is the temperature increase not regular as the amount of zinc is doubled?

6. What happened to the zinc atoms? What happened to the

copper ions? Include in your answer how electrons are involved with these changes.

Grading

grammar and spelling1 pt each

precision error15 points

graph20 pts

correctness of data15 pts

Title page5 pts

Statement of the Problem

Paragraph10 pts

Procedure5 pts

Conclusion30 pts (5 pts per question)

Student Names:

______and ______

Due at the end of the lab period.

Mass of Zn (g) / Initial Temperature of Copper (II) Sulfate Solution (oC) / Final Temperature of Copper (II) Sulfate Solution (oC) / Change in Temperature of Copper (II) Sulfate
Solution (oC) / Qualitative Observations