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, or2)You have 2 moles of ammonium phosphate3)In those 2 formula units, you have 6 atoms of nitrogen, 24 atoms of hydrogen, 2 atoms of phosphorus, 8 atoms of oxygen, or4)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 = 651 S = 1 x 32 = 324 O = 4 x 16 = 64Molar 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 = 78S = 1 x 32 = 32O = 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 g2 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 202 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 %