USING R.I.C.E. TABLES AND STOICHIOMETRY WITH LIMITING REACTANTS RICE tables are a common tool of chemists (college professors use then a lot!) to organize the information for stoichiometry with a reaction and set up mathematical equations when necessary to solve for unknowns. R = reaction (balanced) I = initial conditions (before the reaction) C = change (remove reactants, form products) E = end conditions (after the reaction) Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? BEWARE: Moles goes into a RICE table and moles will come out. To find volume will require a final step. Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + 3O2 → 2CO2 + 2H2O Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= I= C2H4 + 3O2 → 2CO2 + 2H2O Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + I= 10. g 3O2 → 2CO2 + 2H2O Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + 3O2 → I= 10. g 0.625 mol ? 2CO2 + 2H2O 0 0 Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + I= 10. g 0.625 mol ? C= 3O2 → 2CO2 + 2H2O 0 0 Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + I= C= 3O2 → 2CO2 + 2H2O 10. g 0.625 mol ? 0 0 -1x +2x +2x -3x Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + I= 10. g 0.625 mol ? C= 3O2 → 2CO2 + 2H2O 0 0 -1x -3x +2x +2x all the ethene will be burned, so x = 0.63 mol Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + I= 10. g 0.625 mol ? C= 3O2 → 2CO2 + 2H2O 0 0 -1x -3x +2x +2x -0.625 mol -1.875 mol +1.25 mol +1.25 mol Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + I= 10. g 0.625 mol ? C= E= 3O2 → 2CO2 + 2H2O 0 0 -1x -3x +2x +2x -0.625 mol -1.875 mol +1.25 mol +1.25 mol Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? R= C2H4 + 3O2 → I= 10. g 0.625 mol ? 2CO2 + 2H2O 0 0 C= -1x -3x +2x +2x -0.625 mol -1.875 mol +1.25 mol +1.25 mol E= 0 ?-1.875 mol 1.25 mol 1.25 mol Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? How many moles of CO2 was formed? Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? How many moles of CO2 was formed? 1.3 mol Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? How many moles of CO2 was formed? What volume of CO2 was formed? 1.3 mol Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? How many moles of CO2 was formed? What volume of CO2 was formed? 1.25 mol x 22.4 L/mol = 28 L 1.3 mol Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? How many moles of CO2 was formed? What volume of CO2 was formed? 1.25 mol x 22.4 L/mol = 28 L 1.3 mol What other information do we already know? Example 1: 10. grams of ethene is combusted. What volume of carbon dioxide will be formed? How many moles of CO2 was formed? What volume of CO2 was formed? 1.25 mol x 22.4 L/mol = 28 L 1.3 mol What other information do we already know? •Moles of O2 consumed •Moles of H2O produced Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? R= C2H4 + 3O2 → 2CO2 + 2H2O Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? R= C2H4 + 3O2 → I= 10. g 50. g 0.625 mol 1.56 mol 2CO2 + 2H2O Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? R= C2H4 + 3O2 → 2CO2 + 2H2O I= 10. g 50. g 0.625 mol 1.56 mol C= -1x -3x +2x +2x WHICH X TO USE? SMALLEST X! Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? R= C2H4 + 3O2 → 2CO2 + 2H2O I= 10. g 50. g 0.625 mol 1.56 mol C= -1x -3x +2x +2x WHICH X TO USE? SMALLEST X! If 0.625 = 1 x, then x = 0.625 If 1.56 = 3 x, then x = 0.521 ← SMALLEST Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? R= C2H4 + 3O2 → 2CO2 + 2H2O I= 10. g 50. g 0.625 mol 1.56 mol C= -1x -3x +2x +2x -0.521 mol -1.56 mol +1.04 mol 1.04 mol Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? R= C2H4 + 3O2 → 2CO2 + I= 10. g 50. g 0.625 mol 1.56 mol C= -1x -3x +2x +2x -0.521 mol -1.56 mol +1.04 mol 1.04 mol E = 0.625 mol – 0.521 mol 1.56 mol – 1.56 mol 1.04 mol 0.104 mol 0 1.04 mol 2H2O 1.04 mol 1.04 mol Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? What volume of CO2 is actually produced? 1.04 mols x 22.4 L/mol = 23 L Example 2: 10. grams of ethene is combusted with 50. grams of O2. What volume of carbon dioxide can be formed? What volume of CO2 is actually produced? 1.04 mols x 22.4 L/mol = 23 L What else do we know? •Moles of ethene left over •Moles of water actually produced Why use a RICE table for limiting reactant problems? How many RR tracks would it have taken? Why use a RICE table for limiting reactant problems? How many RR tracks would it have taken? 2 to figure out which one is limiting Why use a RICE table for limiting reactant problems? How many RR tracks would it have taken? 2 to figure out which one is limiting 1 more to find amount of excess Why use a RICE table for limiting reactant problems? How many RR tracks would it have taken? 2 to figure out which one is limiting 1 more to find amount of excess 1 more for each of the additional products Why use a RICE table for limiting reactant problems? How many RR tracks would it have taken? 2 to figure out which one is limiting 1 more to find amount of excess 1 more for each of the additional products It is your choice. We did 1 RICE table vs 4 RR Tracks. RICE tables will be necessary later. For now, it is optional.