1. Please take a seat, take out your lab manual, and discuss this problem with your tablemates.
Your last good ping-pong ball fell down into a narrow metal pipe imbedded in concrete one foot deep.  How can you get it out undamaged, if all the tools you have are your tennis paddle, your shoe-laces, and your plastic water bottle, which does not fit into the pipe?

2. Popcorn Lab
What safety rules do we need to follow?

3. Clean-Up Flasks into bin of soap water Popcorn in the trash
All other materials back where you found them
Wash your hands and come back to class

4. Popcorn Calculations
Work with your table to calculate percent by mass of water in your popcorn.

5. The right answer!
Most popcorn will only pop if it has a water content of about 14.5%.

6. The right answer!
Most popcorn will only pop if it has a water content of about 14.5%.
So how close were you?

7. Percent Error
Percent error is a method of analyzing data that tells how accurate our results are
% 𝑒𝑟𝑟𝑜𝑟= (𝐴𝑐𝑡𝑢𝑎𝑙 𝑣𝑎𝑙𝑢𝑒−𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑣𝑎𝑙𝑢𝑒) 𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑣𝑎𝑙𝑢𝑒 ∗100
Actual means what YOU got in the lab.
Make sure you subtract before you divide!

8. Percent Error
% 𝑒𝑟𝑟𝑜𝑟= (𝐴𝑐𝑡𝑢𝑎𝑙 𝑣𝑎𝑙𝑢𝑒−𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑣𝑎𝑙𝑢𝑒) 𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑣𝑎𝑙𝑢𝑒 ∗100
What does it mean about our data if our percent error is 0?
What does it mean about our data if percent error is greater than 100%?
What does it mean about our data if percent error is less than 0?

9. Quiz Friday! We will take quizzes most Fridays in this class
Usually formative scores
Covers anything we’ve done since the last quiz, including labs
This week’s:
Percent composition (mass by percent)
Popcorn lab
Wednesday and Thursday’s stuff (to be announced)

11. ChemCatalyst
You want to analyze a cadmium nitrate solution. What mass of NaOH is needed to precipitate the Cd2+ ions from 35.0 mL of M Cd(NO3)2?

12. Murder Mystery Day 3 Go into the lab and get your final mass
Dump your waste into the provided beaker
Rinse your dishes and put them in the bin
Wash your hands and come back to start working on your calculations

13. My Data Using NaCl Using Na2CO3
20 mL of AgNO3 produced 0.25 g of solid
Using Na2CO3
10 mL of AgNO3 produced 0.13 g of solid

14. Calculations
What is the molarity of the silver nitrate? Who is the murderer?

15. Lab Report Expectations
Expectations might vary from lab to lab
For this lab you need:
Purpose (why did we do this lab? What was the goal?
Brief description of procedure (how did you answer the question?)
Data
Calculations (show all work!)
Conclusion
What does your data mean?
How do you know?
Error analysis – what could have effected your data and HOW

16. Suspect List Professor Plum – 0.20-0.30 M silver nitrate
Mrs. White – M potassium iodide
Mr. Green – M silver nitrate
Mrs. Peacock – >0.20 M potassium iodide
Colonel Mustard – >0.30 M silver nitrate

17. Quiz Friday! Net ionic reactions Murder mystery lab Solubility
Molarity
Wednesday and Thursday’s stuff