Molarity and Dilutions

Pre-LabCalculations & Questions

Take out a piece of paper. You will get into groups of 3-4

students. Pick your groups wisely

Write all your group members names on the top of the paper.

Answer the following questions on the paper.

You MUST get my signature next to each question before moving on.

PART A - Pre-Lab Questions and Calculations1. What is the formula for Copper sulfate

pentahydrate?2. What is the molar mass of Copper sulfate

pentahydrate? (carry to 2 dp)3. What is your assigned molarity for the lab?

(you get this # from Mrs. Hill)4. How many moles of Copper sulfate

pentahydrate will you need to make 100mL of solution?

5. How many grams of Copper sulfate pentahydrate will you need? (carry to 2 dp)

PART A - Procedure Now write a detailed step-by-step

procedure on how you will make 100mL of solution in the molarity Mrs. Hill assigned you.

Minimum of 3 steps. Make it so easy/clear that some one

who has never taken chemistry could follow it.

PART B - Pre-Lab Questions and Calculations6. What is the molarity you will need to

dilute your solution too? (you get this # from Mrs. Hill)

7. Calculate the volume of stock (starting solution) you will need to make 100mL of diluted solution.

8. Write your procedures

PART B - Procedure Now write a detailed step-by-step

procedure on how you will make 100mL of the diluted solution in the molarity Mrs. Hill assigned you.

Minimum of 3 steps. Make it so easy/clear that some one

who has never taken chemistry could follow it.

Post Lab Questions1. Write the formulas for molarity and

dilution.2. List all of the materials/equipment you

used for the lab.3. Calculate the numbers of moles required

to make 100mL of a 3.0M CuSO4●5H2O4. Calculate the numbers of grams required

to make 100mL of a 4.5M CuSO4●5H2O

Post Lab Questions Continued5. How many mL of a 2.0M stock Solution

would be needed to make 100mL of a 0.75M solution?

6. Compare the colors of your stock and diluted solutions, is this what you would expect?

7. If you carefully poured the two together, without mixing them, which would you expect to find on the top layer and which on the bottom?