1. Stoichiometry Examples

2. EXAMPLE 1 What mass of H 2, in grams, will react with 3.3 mol O 2 to produce water? According to the chemical equation:- 2 H 2 + O 2 -----> 2 H 2 O 2mol 1 mol 2 mol X mol 3.3 mol Mass of H 2 = No. of moles x Molar mass of H 2 = [(3.3 x 2) /1] x 2 = 13.2 g = [(3.3 x 2) /1] x 2 = 13.2 g EXAMPLE 2 What mass of H 2, in grams, must react with excess O 2 to produce 5.40 g H 2 O? No. of moles = Mass = 5.4 Molar mass (2x1) + (16x1) = 0.3 mol = 0.3 mol 2 H 2 + O 2 -----> 2 H 2 O 2mol 1mol 2mol X mol 0.3 mol Mass of H 2 = [(2x0.3) /2 ] x (1 x2) = 0.6 g

3. EXAMPLE 3 Calculate the weight of oxygen produced during the thermal decomposition of 100. g of potassium chlorate. potassium chlorate -----> oxygen + KCl -No. of moles of KClO 4 = 100 / [39+35.5+(16x3)] = 0.8163 mol = 0.8163 mol 2 KClO 3 -----> 3 O 2 + 2 KCl 2mol3 mol 2 mol No. of 0.8163molX mol mol of O 2 Mass of O 2 = [(3 x 0.8163) /2] x (16 x 2) = 39.183 g EXAMPLE 4 Ammonia, NH 3, is prepared by the Haber process by the reaction of nitrogen gas with hydrogen gas. How many moles of hydrogen are needed to produce 3.0 kg of NH 3 ? nitrogen + hydrogen -----> ammonia

4. EXAMPLE - No. of moles of NH 3 = 3000 / [14+(1x3)] = 176.4706 mol = 176.4706 mol N 2 + H 2 -----> NH 3 N 2 + 3 H 2 -----> 2 NH 3 1mol 3 mol 2 mol X mol 176.4706 mol X mol 176.4706 mol No. of moles of H 2 = (3 x 176.4706) / 2 = 264.7059 mol EXAMPLE 5 How many moles are in 100 g of CaCO 3 ? How many moles are in 100 g of CaCO 3 ? Molar mass of CaCO 3 = 40 + 12 + (16 x 3) Molar mass of CaCO 3 = 40 + 12 + (16 x 3) = 100 = 100 No. of moles = Mass (g) / Molar mass = 100 / 100 = 100 / 100 = 1 mol = 1 mol

5. EXAMPLE 6 In the reaction BaCO 3 + HCl BaCl 2 + CO 2 + H 2 O - If 2.1 mol of BaCO 3 were present in the start of reaction; how many moles of CO 2 produced ? - If the actual yield of CO 2 is 88.7 g; Calculate the % yield ? - No. of moles of CO 2 = 2.1 mol - Mass of CO 2 = 2.1 x [12 + (16x2) = 92.4 g % yield = [Actual yield / Theoretical yield] x 100 = (88.7 / 92.4) x 100 = 96 % = (88.7 / 92.4) x 100 = 96 %

6. NOMENCLATURES

8. ACIDS HClHydrochloric acid HClHydrochloric acid HBrHydrobromic acid HBrHydrobromic acid HIHydroiodic acid HIHydroiodic acid H 2 SO 4 Sulfuric acid H 2 SO 4 Sulfuric acid HNO 3 Nitric acid HNO 3 Nitric acid H 3 PO 4 Phosphoric acid H 3 PO 4 Phosphoric acid HClO 4 Perchloric acid HClO 4 Perchloric acid

9. BASES NaOHSodium hydroxide NaOHSodium hydroxide KOHPotassium hydroxide KOHPotassium hydroxide Ca(OH) 2 Calcium hydroxide Ca(OH) 2 Calcium hydroxide Ba(OH) 2 Barium hydroxide Ba(OH) 2 Barium hydroxide Mg(OH) 2 Magnesium hydroxide Mg(OH) 2 Magnesium hydroxide Al(OH) 3 Aluminium hydroxide Al(OH) 3 Aluminium hydroxide INORGANIC COMPOUNDS CO 2 Carbon dioxide CO 2 Carbon dioxide COCarbon monoxide COCarbon monoxide SO 2 Sulfur dioxide SO 2 Sulfur dioxide SO 3 Sulfur trioxide SO 3 Sulfur trioxide NH 3 Ammonia NH 3 Ammonia H 2 OWater H 2 OWater P 2 O 5 Phosphorus pentoxide P 2 O 5 Phosphorus pentoxide P 2 O 3 Phosphorus trioxide P 2 O 3 Phosphorus trioxide

10. SALTS NaCl Sodium chloride NaCl Sodium chloride KBr Potassium bromide KBr Potassium bromide CaSO 4 Calcium sulfate CaSO 4 Calcium sulfate MgI 2 Magnesium iodide MgI 2 Magnesium iodide Ba(NO 3 ) 2 Barium nitrate Ba(NO 3 ) 2 Barium nitrate Ba 3 (PO 4 ) 2 Barium phosphate Ba 3 (PO 4 ) 2 Barium phosphate NaNO 2 Sodium nitrite NaNO 2 Sodium nitrite SALTS LiCl. H 2 O Lithium chloride monohydrate LiCl. H 2 O Lithium chloride monohydrate Na 3 N Sodium nitride Na 3 N Sodium nitride CuCl Copper(I) chloride CuCl Copper(I) chloride FeO Iron(II) oxide FeO Iron(II) oxide Fe 2 O 3 Iron(III) oxide Fe 2 O 3 Iron(III) oxide CuO Copper(II) oxide CuO Copper(II) oxide MnO 2 Manganese(IV) oxide MnO 2 Manganese(IV) oxide MnO Manganese(II) oxide MnO Manganese(II) oxide

11. SALTS CrO 3 Crumium(VI) oxide CrO 3 Crumium(VI) oxide CuSO 4.5H 2 O Copper(II) sulfate pentahydrate CuSO 4.5H 2 O Copper(II) sulfate pentahydrate BaCl 2. 2H 2 O Barium chloride dihydrate BaCl 2. 2H 2 O Barium chloride dihydrate CuCl 3 Copper(III) chloride CuCl 3 Copper(III) chloride KClO 4 Potassium perchlorate KClO 4 Potassium perchlorate Ba(ClO 4 ) 2 Barium perchlorate Ba(ClO 4 ) 2 Barium perchlorate Na 2 S Sodium sulfide Na 2 S Sodium sulfide