# Wednesday, May 4 th : “A” Day Thursday, May 5 th : “B” Day Agenda  Lab Calculations: “Percent Composition of Hydrates”  Collect Lab  Movie: “Strong.

• Published on
22-Dec-2015

• View
212

• Download
0

Embed Size (px)

Transcript

<ul><li> Slide 1 </li> <li> Slide 2 </li> <li> Wednesday, May 4 th : A Day Thursday, May 5 th : B Day Agenda Lab Calculations: Percent Composition of Hydrates Collect Lab Movie: Strong Chemistry </li> <li> Slide 3 </li> <li> 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. </li> <li> Slide 4 </li> <li> 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. </li> <li> Slide 5 </li> <li> 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. </li> <li> Slide 6 </li> <li> Lab: Percent Composition of Hydrates 5.Interpreting information Use complete sentences to answer this question on your own. </li> <li> Slide 7 </li> <li> 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: CuSO 4 X H 2 O Where X is the whole-number ratio of moles of water </li> <li> Slide 8 </li> <li> 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 </li> <li> Slide 9 </li> <li> 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 H 2 O = 13.6 g H 2 O 3.25 g CuSO 4 </li> <li> Slide 10 </li> <li> Lab: Percent Composition of Hydrates 9.Applying conclusions Use complete sentences to answer this question on your own. </li> <li> Slide 11 </li> <li> 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 </li> <li> Slide 12 </li> <li> 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! </li> </ul>