Friday March 27 Objective: Determine the limiting reactant in a chemical reaction. Determine how much product can be made. Checkpoint: Given the equation: 2 H 2 + O 2 2 H 2 O If you have 0.50 grams of H 2, how many grams of H 2 O can you make if everything goes perfectly (your theoretical yield)? Not all of your oxygen reacted and you only made 2.15 grams of water. What is your percent yield? Homework: – Limiting Reactant notes & problems (due Monday) – Stoichiometry study guide (due Wed/Thurs), test on Friday
0.50 g H 2 X g H 2 O mol H 2 O X X mol H 2 g H g H 2 O (theoretical yield) mol H 2
Not all of your oxygen reacted and you only made 9.25 grams of water. What is your percent yield? actual yield % yield = x 100 theoretical yield 2.15 g H 2 O (actual yield) 4.46 g H 2 O (theoretical yield) 2.15 g x 100= % yield 4.46 g
MgO Lab Report (1 day 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?
Limiting Reactants Exercise Google Slides Presentation (1 presentation per group of 4) share with – Title Slide (with class name and group member names) – Slide that restates the problem. – Solution to the problem. – Pictures / Graphics with your procedure.
Limiting Reactants 2 H 2 + O 2 2 H 2 O If you have 10.0 grams of hydrogen and 15.0 grams of oxygen, how much water can you make? If you have 5 pieces of bread and 4 hamburger patties, how many hamburgers can you make?
Making a Gas Lab CH 3 COOH + NaHCO 3 CH 3 COOHNa + H 2 O + CO 2 If you are finished, you may work on the study guide due (Wed/Thurs)
CH 3 COOH + NaHCO 3 CH 3 COOHNa + H 2 O + CO mol baking soda 0.08 mol baking soda 0.16 mol baking soda
CH 3 COOH + NaHCO 3 CH 3 COOHNa + H 2 O + CO mol baking soda 0.08 mol baking soda 0.16 mol baking soda 0.08 mol vinegar
1 hamburger 2 hamburgers
Limiting Reactant
82p+83s+45b=how much left over? 41(2p+2s+1b=Bed) 82p+82s+41b=41 Beds
2 H 2 + O 2 2 H 2 O What is your limiting and excess reactants if you have 5.43 grams of hydrogen and grams of oxygen? 5.43 g H 2 g H 2 O g O 2 g H 2 O g H 2 O g H 2 O Limiting reactant Excess reactant
2 H 2 + O 2 2 H 2 O What is your limiting and excess reactants if you have 5.43 grams of hydrogen and grams of oxygen? 5.43 g H 2 mol H g O 2 mol O mol H mol O 2 O 2 = Limiting reactant H 2 = Excess reactant 5.43 g H 2 X mol H 2 g H g O 2 X mol O g O 2 / 2 /
Balance the reactions first!!!