Sample Lab Questions Investigation #10: "Copper(II) and Algae"

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1.

(1pt) Was the copper(II) ion more easily detected in a pure water solution or a solution of ammonia? How could you tell?

2.

(2pts) Explain briefly how you determined the density of your algaecide solution.

3.

(2pts) Define the following units of concentration:

(a) molarity (M)

(b) parts per million (ppm)

4.

a. (1pt) Sketch what is meant by the bottom of the meniscus in a buret.

b. (1pt) To how many decimal places should you read a buret?

5.

(1pt) The diet of any living organism must contain not only the proper elements, but also the proper range of their concentrations. Why?

6.

a. (1pt) Describe the process of dilution.

b. (3pts) Calculate the volume of 6.00 x 10^-3 M CuSO₄5H₂O solution required to prepare 100.0 mL of 4.50 x 10^-4 M CuSO₄5H₂O solution.

7.

(2pts) Calculate the mass of CuSO₄5H₂O required for the preparation of 100.0 mL of 6.00 x 10^-3 M solution.

8.

a. (3pts) Calculate the number of milligrams of Cu²⁺ in 1.00 L of solution of 4.50 x 10^-4 M CuSO₄5H₂O.

b. (3pts) Assuming a solution density of 1.01 g/mL, what is the concentration of Cu²⁺ (in ppm) of this solution?

9.

(3pts) A student prepared 3 aqueous solutions of CuSO₄ according to the following procedures. Calculate the moarities of CuSO₄ for solutions I, II, and III.

Solution I: 0.4344 g of CuSO₄5H₂O was dissolved and diluted to 100.0 mL

Solution II: 8.28 mL of Solution I was diluted to 100.0 mL

Solution III: 38.20 mL of Solution II was diluted to 100.0 mL.

Answers

6.	b.	7.50 mL solution
7.		0.150 g
8.	a.	28.6 mg
	b.	28.3 ppm
9.		Solution I: 0.01740 M CuSO4
		Solution II: 0.001441 M CuSO4
		Solution III: 5.505 x 10-4 M CuSO4

To report any corrections, please e-mail Dr. Wendy Keeney-Kennicutt.