1. Wed/Thurs April 1 Objective: Calculate how much excess reactant is left over in a chemical reaction. Checkpoint: Given the equation: 2 H 2 + O 2  2 H 2 O You have 34.1 grams of H 2 and 334.12 grams of O 2. How much water will you make? How much excess reactant will be left over? Homework: – Study for exam on Friday – LR extra credit wksht due Friday

2. 34.1 g H 2 X g H 2 O mol H 2 O X X mol H 2 g H 2 2.02 1 1 18.02 2 2 304.20 g H 2 O mol H 2 You have 34.1 grams of H 2 and 334.12 grams of O 2. How much water will you make? 334.12 g O 2 X g H 2 O mol H 2 O X X mol O 2 g O 2 32.00 1 1 18.02 1 2 mol O 2 376.30 g H 2 O Limiting reactant

3. 34.1 g H 2 X g H 2 O mol H 2 O X X mol H 2 g H 2 2.02 1 1 18.02 2 2 304.20 g H 2 O mol H 2 You have 34.1 grams of H 2 and 334.12 grams of O 2. How much water will you make? 334.12 g O 2 X g H 2 O mol H 2 O X X mol O 2 g O 2 32.00 1 1 18.02 1 2 mol O 2 376.30 g H 2 O Limiting reactant This is how much water you will make

4. You have 34.1 grams of H 2 and 334.12 grams of O 2. How much excess reactant will be left over? Limiting reactantExcess reactant grams of limiting reactant  grams of excess reactant 34.1 grams H 2  grams O 2 34.1 g H 2 X g O 2 mol O 2 X X mol H 2 g H 2 2.02 1 1 32.00 2 1 mol H 2 270.10 g O 2 used 334.12 g – 270.10 g = 64.02 g O 2 left

5. MgO Lab Report (4 days late) Pre-lab questions Data Table (with units) Calculations (show your work, box your answer) Conclusion: – Did you meet your goal of making exactly 0.50 grams of MgO? – Restate the value you got for % yield. – What are some sources of error in your experiment that prevented you from getting 100% yield and 0 % error?

6. CH 3 COOH + NaHCO 3  CH 3 COOHNa + H 2 O + CO 2 0.04 mol baking soda 0.08 mol baking soda 0.16 mol baking soda 0.08 mol vinegar

8. Limiting Reactants of Smores 2 graham cracker + 1 marshmallow + 3 chocolate  1 smore

9. Limiting Reactants of Smores What is the limiting reactant? What are your excess reactants? How many smores can you make? How much excess reactant will be left over? 74.70 grams graham cracker 19.00 grams of marshmallow 31.56 grams of chocolate

10. Limiting Reactants of Smores Clean up your lab space first. It currently has baking soda and vinegar residue. Take turns using the sticks. Do not throw sticks or plates away! You don’t have to wear safety glasses as long as you are very very very careful. Don’t be that guy. No flaming marshmallows in the eye.