Wednesday, May 4th: “A” DayThursday, May 5th: “B” Day

Agenda

Lab Calculations: “Percent Composition of Hydrates”

Collect LabMovie: “Strong Chemistry“

Lab Calculations: “Percent Composition of Hydrates”

Next to your data table, enter the initial mass of copper (II) sulfate that you started with.

Initial mass of sample, crucible, and cover MINUS the mass of empty crucible and cover.

Lab Calculations: “Percent Composition of Hydrates”

3. Examining Data Find the mass of anhydrous copper (II) sulfate

by subtracting the mass of the empty crucible and cover from the constant mass of sample, crucible, and cover.

Calculate the molar mass of copper (II) sulfate.

Convert mass of copper (II) sulfate to moles by dividing by the molar mass of copper (II) sulfate.

Lab: “Percent Composition of Hydrates”

4. Analyzing Data Find the mass of water in the sample by

subtracting the mass after heating from the mass before heating.

Calculate the molar mass of water.

Convert mass of water to moles by dividing by the molar mass of water.

Lab: “Percent Composition of Hydrates”

5. Interpreting information Use complete sentences to answer this

question on your own.

Lab: “Percent Composition of Hydrates”

6. Drawing Conclusions Find the empirical formula by dividing each number of

moles found in questions 3 and 4 by the smallest number of moles found.

This will give you the ratio of copper (II) sulfate to water molecules.

What is your ratio? Write the empirical formula for the hydrate using the

following format:CuSO4• X H2O

Where “X” is the whole-number ratio of moles of water

Lab: “Percent Composition of Hydrates”

7. Analyzing Results Find the percentage by mass of water in the original

hydrated compound by dividing the mass of water you found in the sample (in grams) by the total mass of sample you started with (about 5 g) and multiplying by 100%.

Mass of water in hydrated sample X 100% Initial mass of hydrated sample

Lab: “Percent Composition of Hydrates”

8. Applying Conclusions Start with what you know, 25 grams of

anhydrous copper (II) sulfate. Multiply by the mass of water contained in

the 5g sample (in grams). Divide by the mass of anhydrous copper

sulfate (in grams).

25g X 1.77 g H2O = 13.6 g H2O

3.25 g CuSO4

Lab: “Percent Composition of Hydrates”

9. Applying conclusions Use complete sentences to answer this

question on your own.

Lab: “Percent Composition of Hydrates”

Make sure your data is all properly labeled with the correct units.

Staple your lab write-up to the front of the lab handout.

Make sure your table of contents is updated.Turn in…

Movie:“Strong Chemistry“

For extra credit, write down 20 things you learned from the movie…

I expect you to stay awake, stay off your phones, and PAY ATTENTION!