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WHERE DO YOU LOOK IF YOU’VE LOST YOUR MIND? -Bernard Malamud- REVIEW WHAT INFORMATION DOES THE FOLLOWING FORMULA TELL YOU? 2 (NH4)3PO4 WHAT INFORMATION DOES THE FOLLOWING FORMULA TELL YOU? 2 (NH4)3PO4 1)You have 2 formula units of ammonium phosphate, or 2)You have 2 moles of ammonium phosphate 3)In those 2 formula units, you have 6 atoms of nitrogen, 24 atoms of hydrogen, 2 atoms of phosphorus, 8 atoms of oxygen, or 4)In those 2 moles, you have 6 moles of nitrogen, 24 moles of hydrogen, 2 moles of phosphorus, and 8 moles of oxygen CALCULATE THE MOLAR MASS OF ZnSO4. CALCULATE THE MOLAR MASS OF ZnSO4. 1 Zn = 1 x 65 = 65 1 S = 1 x 32 = 32 4 O = 4 x 16 = 64 Molar Mass = 161 g/mole HOW MANY MOLES OF K2SO4 ARE IN 20 GRAMS? HOW MANY MOLES OF K2SO4 ARE IN 20 GRAMS? First, calculate the molar mass: K = 2 x 39 = 78 S = 1 x 32 = 32 O = 4 x 16 = 64 •Molar mass = 174 g/mole # moles = 20 g / 174 g/mole = 0.115 mole HOW MANY MOLECULES OF C2H5OH ARE IN 2.5 MOLES? HOW MANY MOLECULES OF C2H5OH ARE IN 2.5 MOLES? 1 mole = 6.023 x 1023 molecules # molecules = 2.5 moles x 6.023 x 1023 molecules/mole = 1.51 x 1024 molecules HOW MANY GRAMS OF PbI2 ARE IN 8.4 X 1022 MOLECULES? HOW MANY GRAMS OF PbI2 ARE IN 8.4 X 1022 MOLECULES? # moles = 8.4 x 1022 / 6.023 x 1023 = 1.39 x 10-1 = 0.139 moles Molar mass of PbI2 = 207 + 2(127) = 461 g/mole # grams = 461 g/mole x 0.139 moles = 64 g BALANCE THE FOLLOWING EQUATIONS, AND TELL WHAT KIND OF REACTION THE EQUATION REPRESENTS: a.C4H10 + O2 → CO2 + H2O b.Fe + Cl2 FeCl3 c.Cu + AgNO3 Cu(NO3)2 + Ag d.Pb(NO3)2 + AlCl3 Al(NO3)3 + PbCl2 e.KClO3 KCl + O2 BALANCE THE FOLLOWING EQUATIONS, AND TELL WHAT KIND OF REACTION THE EQUATION REPRESENTS: a.2 C4H10 + 13 O2 → 8 CO2 + 10 H2O b.2 Fe + 3 Cl2 2 FeCl3 c.Cu + 2 AgNO3 Cu(NO3)2 + 2 Ag d.3 Pb(NO3)2 + 2 AlCl3 2 Al(NO3)3 + 3 PbCl2 e.2 KClO3 2 KCl + 3 O2 WHAT ARE THE SUBSTANCES ON THE LEFT SIDE OF A CHEMICAL REACTION CALLED? WHAT ARE THE SUBSTANCES ON THE RIGHT SIDE OF CHEMICAL REACTION CALLED? WHAT ARE THE SUBSTANCES ON THE LEFT SIDE OF A CHEMICAL REACTION CALLED? REACTANTS WHAT ARE THE SUBSTANCES ON THE RIGHT SIDE OF CHEMICAL REACTION CALLED? PRODUCTS WHAT IS THE LAW OF CONSERVATION OF MASS? WHAT IS THE LAW OF CONSERVATION OF MASS? IN A CHEMICAL REACTION, MATTER IS NEITHER CREATED OR DESTROYED, ONLY REARRANGED. HOW DOES THE LAW OF CONSERVATION OF MASS APPLY TO A CHEMICAL EQUATION? HOW DOES THE LAW OF CONSERVATION OF MASS APPLY TO A CHEMICAL EQUATION? YOU HAVE THE SAME NUMBER OF EACH TYPE OF ATOMS ON BOTH SIDES OF THE EQUATION – THE EQUATION IS BALANCED. 2 NH3 + H2SO4 (NH4)2SO4 How many grams of ammonia (NH3) would be required to make 1 kilogram of ammonium sulfate? How many grams of ammonia (NH3) would be required to make 1 kilogram of ammonium sulfate? X 1000 g 2 NH3 + H2SO4 (NH4)2SO4 34 128 X / 34 = 1000 / 128 X = (1000 x 34) / 128 = 265.6 g Note: molar mass of ammonium sulfate = 128 g/mole molar mass of ammonia = 17 g/mole How many moles of iron, Fe, would be required to make 40 grams of hydrogen, H2? 2 Fe + 6 HCl 2 FeCl3 + 3 H2 How many moles of iron, Fe, would be required to make 40 grams of hydrogen, H2? 2 Fe + 6 HCl 2 FeCl3 + 3 H2 Molar mass of H2 = 2 g/mole # moles H2 = 40 g/2 g/mole = 20 moles X 20 2 Fe + 6 HCl 2 FeCl3 + 3 H2 2 3 X/2 = 20/3 so X = 20/3 x 2 = 13.3 moles A COMPOUND CONTAINS THE ELEMENTS COPPER AND CHLORINE IN A RATIO OF 1 COPPER : 2 CHLORINE. WHAT IS THE EMPIRICAL FORMULA FOR THIS COMPOUND? WHAT IS THE % COMPOSITIONOF COPPER? WHAT IS THE % COMPOSITION OF CHLORINE? EMPIRICAL FORMULA: CuCl2 Molar mass = 63.5 + 2(35.5) = 134.5 g/mole % Cu = (63.5 / 134.5) x 100 = 47.2 % % Cl = (71 / 134.5) x 100 = 52.8 %