2. Notes #3 Grams to grams stoichiometry 4- step bridge

3. MASS-MASS STOICHIOMETRY!! n Example: How many grams of silver chloride are produced when 17.0 grams of silver (I) nitrate react with excess sodium chloride?

4. Mass - Mass Relationships Ê Write a balanced equation for the reaction. (Remember to look up the oxidation numbers so the formulas are correct). Ê Start with mass given. Ë Calculate the number of moles of the “given” substance. Ì Use the mole ratio to determine the moles of the “required” (unknown) substance to moles of the “given” substance.(Use the balanced equation.) Í Convert moles “required” to grams (molar mass conversion factor) Í.Í. AgNO 3 = 170g/mole(molar mass conversion factor)

5. Mass - Mass Relationships AgNO 3 + NaCl  AgCl + NaNO 3 Start w/ grams given 17.0 g AgNO 3 169.88g AgNO 3 1 Mole AgNO 3 1 mole of given Grams of given Moles “required” Moles given 1 mol AgCl 1 mol AgNO 3 Grams of “required” 1 mole “required” grams produced = 143.32 gAgCl 1 mol AgCl = 14.3 g AgCl givenrequired

6. Problems: n How much silver carbonate is produced when 14.3 g of silver chloride reacts with excess sodium carbonate? n What kind of reaction is this? Double displacement. Write the balanced equation. AgCl + Na 2 CO 3  22Ag 2 CO 3 + NaCl

7. 2AgCl + Na 2 CO 3  Ag 2 CO 3 + 2NaCl Given 14.3g AgCl Grams per mole Moles of silver carbonate Moles of silver chloride 1 mol Ag 2 CO 3 2 mol AgCl Grams per mole of required substance 277 g Ag 2 CO 3 1 mol Ag 2 CO 3 = 13.9 g Ag 2 CO 3 143g AgCl 1 mol AgCl

8. Practice problems 1. In a spacecraft, the carbon dioxide exhaled by astronauts can be removed by its reaction with lithium hydroxide according to the following equation: CO 2 (g) + 2LiOH Li 2 CO 3 (s) + H 2 O (l) How many moles of lithium hydroxide are required to react with 20 moles of caron dioxide?