Review Book & Mid-TermTopics covered to date:

• Topic 1 – Atoms

• Topic 2 – Formulas and Equations

• Topic 3 – Chemistry Math

• Topic 4 – Matter

• Topic 5 – Periodic Table

• Topic 6 - Bonding

You must choose 4 for mid-term

Stoichiometry

AKA Chemistry Math

BELL RINGER

How many atoms are in a mole of carbon?

“my avogadro don't want none unless you've got moles hun”

Ridiculous Mole Facts

3 moles of M&M’s would fill the entire earths oceans (an equivalent amount of water would fill about a ¼ cup)

1 mole of donut holes will cover the earth to a depth of seven miles!

1 mole of pennies would reach to the moon 7-8 times.

Ridiculous Mole Facts

One mole of seconds is about 19 quadrillion years, 4,240,666 times the age of the earth, or 954,150 times the age of the universe itself.

A one liter bottle of water contains 55.5 moles of water.

If you started with a mole of pennies and spent $1,000,000 every second for 100 years, you would still have more than

99.99% of what you started with. 

Are all moles created equally?

In chemistry, how an atom reacts is dependent on the number of atoms, not the mass of the atoms.

For example, if you have 100.0 g of Na and react that with 100.0 g of Chlorine they would not react completely.

• Chlorine starts out with a mass of 35.5 and Na has a mass of 23

• As a result, we would have a bunch of Na atoms unused.

• In chemistry it is much easier to use a quantity of atoms rather than a mass of atoms

VS

A nice mole song!

Avogadro Style

Moles

What is the mass of a Carbon atom?

12.0 amuIf one mole of Carbon atom’s have a

mass of 12.0g, how many atoms would that be?

That would be 6.02 x 1023 atoms of carbon

Gram Formula Mass

(molar mass)

= the mass of one mole of something

Let’s try out water: H2O

H

O

2

1

x 1.0

x 16.0

= 2.0

= 16.0

18.0 g/mol

Therefore, 1 mole of water has a mass of 18g/mol.

GFM (practice)

Let’s try magnesium hydroxide: Mg(OH)2

Mg

O

1

2

x 24.3

x 16.0

= 24.3

= 32.0

58.3 g/mol

H 2 x 1.0 = 2.0

GFM - Hydrates

Na2CO3●10H20Sodium Carbonate crystals:Na

C

2

1

x 23.0

x 12.0

= 46.0

= 12.0

286.0 g/mol

0 3 x 16.0 = 48.0

Hydrate - is a crystalline compound in which ions are attached to one or more WATER molecules

H20 10 x 18.0 = 180.0

BELL RINGER

What is the gfm of NH4?

GFM = 18Moles = 72.0 ÷ 18.0 = 4 moles

“my avogadro don't want none unless you've got moles hun”

Converting to moles

If you have 63g of water how many moles of water do you have?

1. Determine the gfm: 18 g/mol

Number of molesgiven mass (g)

gram-formula mass=

Number of moles63g

18g/mol= = 3.5 moles

ConversionsMoles to Grams

1. How many g are in 0.0700 moles of H2O2?Number of moles

given mass (g)

gram-formula mass=

2. How many g are in 1.20 moles of CaCO3?

3 4 .0 g /m o le

xs0 .0 7 0 0 m o le

g3 8.2x

e100.1g/mol

x1.20moles

mol.120x

GFM Practice1. NaBr

2. PbSO4

3. Ca(OH)2

4. Na3PO4

5. (NH4)2CO3

6. C6H12O6

7. Fe3(PO4)2

8. (NH4)2S

9. Zn(C2H3O2)2

10. AgF

GFM Practice1. NaBr

2. PbSO4

3. Ca(OH)2

4. Na3PO4

5. (NH4)2CO3

6. C6H12O6

7. Fe3(PO4)2

8. (NH4)2S

9. Zn(C2H3O2)2

10. AgF

102.9 g/mol

303.3 g/mol

74.1 g/mol

164.0 g/mol

96.0 g/mol

180.0 g/mol

357.4 g/mol

68.1 g/mol

183.4 g/mol

126.9 g/mol

BELL RINGER

You have 72.0g of NH4. How many moles do you have?

GFM = 18.0Moles = 72.0 ÷ 18.0 =

4.00 moles

GFMWHITEBOARD REVIEW

Sodium Hydrogen Carbonate

ZincSodium CarbonateWater

SucroseC12H22O11Aluminum

Sodium ChlorideIronCopper (II)

sulfate●pentahydrate

Some Practice1. What is the gfm for Calcium nitrate?

Number of molesgiven mass (g)

gram-formula mass=

Number of moles10.2g

164.1g/mol= = 0.0622 moles

2. How many moles of calcium nitrate do you have if you have 10.2 g?

Criss-cross to get the formula: Ca(NO3)2

Ca

N

1

2

x 40.1

x 14.0

= 40.1

= 28.0

O 6 x 16.0 = 96.0

164.1 g/mol

Practice Problems

GFM = 122.6 g Number of moles

given mass (g)

gram-formula mass=

Number of moles40.8 g

122.6g= = 0.333 moles

1. If you have 40.8g of KClO3. How many moles do you have?

2. You have 2.5 moles of KClO3. How many grams is that? GFM = 122.6 g

Grams = GFM x # moles

Grams = 122.6g/mol x 2.5 moles = 306.5 g = 310 g

Percent Composition

-used to find the percentage by mass of an element in a compound

What are the % of elements in dihydrogen monoxide? H2O

1 0 0% xw h o leo fm a s s

p a r to fm a s sc o m p

H 2 x 1.0 = 2.0

O 1 x 16.0 = 16.0

%= 2.0/18.0 = 11%

%= 16.0/18.0 = 88.9%

18.0 g

Percent Composition

What are the % of elements in potassium nitrate? KNO3

1 0 0% xw h o leo fm a s s

p a r to fm a s sc o m p

K 1 x 39.1 = 39.1

O 3 x 16.0 = 48.0

% = 39.1/101.1 = 38.7%

% = 48.0/101.1 = 47.5%

101.1 g

N 1 x 14.0 = 14.0 % = 14.0/101.1 = 13.8%

Percent Composition

What is the percentage of water in the following compound CoCl2•6H2O

Co 1 x 58.9 = 58.9

H2O 6 x 18.0 = 108.0

% = 58.9/237.9 = 24.8%

% = 108.0/237.9 = 45.40%

237.9 g/mol

Cl 2 x 35.5 = 71.0 % = 71.0/237.9 = 29.8%

Hydrate

Percent Composition

What is the percentage of water in the following compound CaSO4•5H2OCa 1 x 40.1 = 40.1

O 4 x 16.0 = 64.0

226.2 g/mol

S 1 x 32.1 = 32.1

Hydrate

H2O 5 x 18.0 = 90.0 % = 90.0/226.2 = 39.8%

BELL RINGER

How many grams is 0.36 moles of potassium permanganate?

Empirical and Molecular Formulas

Empirical Formula = the formula of a compound expressed as the smallest possible whole-number ratio of subscripts of the elements in the formula

Molecular Formula = the formula of a compound in which the subscripts give the actual number of each element in the formula

Empirical and Molecular Formulas

Molecular Formula Empirical Formula

H2O

CH3COOH

CH2OH

WO2

B2H6

C6H12O6

H2O

CH2O

CH2OH

WO2

BH3

CH2O

Empirical and Molecular Formulas

A compound with an empirical formula of C2OH4 and a molar mass of 88 grams per mole. What is the molecular formula of the compound?

Empirical and Molecular Formulas

A well known reagent in analytical chemistry, dimethylglyoxime, has the empirical formula C2H4NO. If its molar mass is 116.1g/mol, what is the molecular formula of the compound?

BELL RINGER

What are the empirical formulas for the following?

C6H6

CH2ClCH3

HC2H3O2

Determining Formulas from %Percent to massMass to molesDivide by small

Multiply ‘til whole

A compound consists of 72.2% magnesium and 27.8% nitrogen by mass. What is the empirical formula?

1. Assume 100g, so you have: 72.2g Mg and 27.8g N

2. Convert to moles

Mg - 72.2/24.3

N – 27.8/14.0

= 2.97 moles

= 1.99 moles

Determining Formulas from %Percent to massMass to molesDivide by small

Multiply ‘til whole

3. Divide by small

Mg 2.97 / 1.99

N 1.99 / 1.99

= 1.49

= 1.00Mg1.49N1.00 ???

4. Multiply ‘til whole

Mg 1.49

N 1

X 2 = 3

X 2 = 2 Mg3N2

Hydrate Problem• In lab, a student determined that a

hydrate of barium chloride contained 14.0% water. What is the actual numbers of water molecules for each molecule of barium chloride. Basically the formula of the hydrate.

REMEMBER

Barium Chloride

Water 14.0%

Hydrate Problem

BELL RINGERProblem: A compound contains 32.4% sodium, 22.1% sulfur and 45.0% oxygen. What is the empirical formula?

• Na 32.4g

• S22.1g

• O45.0g

÷ 23.0

÷ 32.1

÷ 16.0

= 1.41 mol

= 0.688 mol

= 2.81 mol

÷ .688

÷ .688

÷ .688

= 2.05

= 1.00

= 4.09

As a result the formula would be:

Na2SO4

Hydrate PracticeA calcium chloride hydrate has a mass of 4.72 g. After heating for several minutes the mass of the

anhydrate is found to be3.56 g. Use this information to determine the

formula for the hydrate.

Calcium Chloride

Water

Mass of Hydrate = 4.72g

Hydrate Practice (lab problem)

Anhydrous = 3.56g

CHEMICAL REACTIONS

Reactants: Zn + I2 Product: Zn I2

Because of the principle of the law conservation of matter,

an equation must be balanced.

It must have the same number of each kind of atoms on both sides.

Lavoisier 1788

Chemical Equations

Chemical EquationsTheir Job: Depict the kind of

reactants and products and their relative amounts in a reaction.

Al (s) + O2 (g) ---> Al2O3 (s)

The numbers in the front are called

stoichiometric ____________coefficients

4 3 2

• Solid (s)• Liquid (l)• Gas (g)• Aqueous solution (aq)• Catalyst H2SO4

• Escaping gas ()• Change of temperature ()

Symbols Used in Equations

Balancing Equations

When balancing a chemical reaction you may add coefficients in front of the

compounds to balance the reaction -

but you may not change the subscripts.

Changing the subscripts changes the compound. Subscripts are determined by the valence electrons (charges for ionic

or sharing for covalent)

Subscripts vs. Coefficients

• The subscripts tell you how many atoms of a particular element are in a compound. The coefficient tells you about the quantity, or number, of molecules of the compound.

1. The coefficients of a chemical reaction indicate relative amounts of reactants and products.

Coefficients are MOLE RATIOS

Example: H2(g) + Cl2(g) 2HCl(g)

1 mol H2 : 1 mol Cl2 : 2 moles HCl

2. The relative masses of the reactants and products can also be determined from the coefficients.

Example:

1 mol H2 = 2.02 g H2

1 mol Cl2 = 70.90 g Cl22 mol HCl = 72.92 g HCl

Therefore, 2.02g H2 will react with 70.90g Cl2 to form 72.92g of HCl.

Why are we learning this?

1.Compare the numbers of atoms on each side of the equation

2.Start with the most complicated molecules FIRST!

3.Leave H and O until the end4.Place COEFFICIENTS in front of the

compound to try and balance the atoms5.Check your answer to see if:

- The numbers of atoms on both sides of the equation are now balanced.

6.Reduce if possible!!!!

Steps to Balancing Equations

___ Al(s) + ___ Br2(l) ---> ___ Al2Br6(s)2 3

Steps to Balancing Equations

Online Balancing Equations

Click on picture above to go to the site!

Balancing EquationsBalancing Equations

____C3H8(g) + _____ O2(g) ---->

_____CO2(g) + _____ H2O(g)

____B4H10(g) + _____ O2(g) ---->

___ B2O3(g) + _____ H2O(g)

3 4

5

2 54 10

112

BELL RINGERBalance the following:Sodium phosphate + iron (III) oxide sodium oxide + iron (III) phosphate

Na3PO4 + Fe2O3 ----> Na2O + FePO4 2 3 2

BELL RINGER

Balance the following:

Ca(OH)2 + H3PO4 → Ca3(PO4)2 + H2O

• Balancing wkst

__Al + __O2 __Al2O2

Practice Balancing Equations

2

__Fe2O3 + __H2SO4 __Fe2(SO4)3 + __H2O

__ Fe + __Cl2 __ FeCl33 22

3 3

__KClO3 → __KCl + __O22 32

Write out the following chemical equation

Methane reacts with oxygen to produce carbon dioxide and water

CH4 + O2 CO2 + H2O

Practice

Write out the following chemical equation

Hydrogen gas reacts in the presence of oxygen gas to explode and produce liquid water.

H2(g) + O2(g) H2O(l)

Practice

+energy

BELL RINGER

What is the IUPAC name of the following compound?

Mn2O3

Chemical EquationsChemical Equations4 Al(s) + 3 O2(g)

---> 2 Al2O3(s)

This equation means

4 Al atoms + 3 O2 molecules ---produces--->

2 molecules of Al2O3

AND/OR

4 moles of Al + 3 moles of O2 ---produces--->

2 moles of Al2O3

Types of Reactions

1. Synthesis reactions

2. Decomposition reactions

3. Combustion reactions

4. Single replacement reactions

5. Double Replacement reactions• You need to be able to identify the type

of reaction and predict the product(s)

There are five types of chemical reactions we will talk about:

1. Synthesis Reactions• Synthesis reactions occur when two

substances (generally elements) combine and form a compound. (Sometimes these are called combination or addition reactions.)

reactant + reactant 1 product• Basically: A + B AB

• Example: 2H2 + O2 2H2O

• Example: C + O2 CO2

DEMO: Write the reaction for the synthesis of MgO(s)

Mg(g) + O2(g) MgO(s)22

Zn powder + Sulfur – See Hilt

2. Decomposition Reactions• Decomposition reactions occur when a

compound breaks up into the elements or in a few to simpler compounds

• 1 Reactant Product + Product • In general: AB A + B• Example: 2 H2O 2H2 + O2

• Example: 2 HgO 2Hg + O2

Elephant’s Toothpase

• Write the reaction for the decomposition of hydrogen peroxide (H2O2)

H2O2 H2O + O222

Decompostion of KBrO3 – See Hilt

Practice

• Predict the products. Then, write and balance the following decomposition reaction equations:

• Solid Lead (IV) oxide decomposes

• The formation of sulfur dioxide

PbO2(s) Pb + O2

S + O2 SO2

3. Combustion Reactions• Combustion is actually an organic reaction• Organic Compound + O2 CO2 + H2O

• Methane Mamba

CH4 + O2 CO2 + H2O

BELL RINGER

Write and balance the following:

Decomposition of ammonia

Formation of calcium chloride

4. Single Replacement Reactions

• Single Replacement Reactions occur when one element replaces another in a compound.

• A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-).

• Must refer to Table J• element + compound different element + different compound

A + BC AC + B (if A is a metal) OR

A + BC BA + C (if A is a nonmetal) (remember the cation(+) always goes first!)

When H2O splits into ions, it splits into

H+ and OH- (not H+ and O-2 !!)

Practice• Sodium chloride solid reacts with fluorine gas

NaCl(s) + F2(g) 2 2

Aluminum metal reacts with aqueous copper (II) nitrate

Al(s) + Cu(NO3)2 (aq) Cu + Al(NO3)33 232

NaF(s) + Cl2(g)

5. Double Replacement Reactions

• Double Replacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound

• Compound + compound product + product• AB + CD AD + CB

Double Replacement Reactions

• Mixed doubles in tennis, can the guy switch with a girl?

• Example:

AgNO3(aq) + NaCl(s) AgCl(s) + NaNO3(aq)

Double Replacement Reactions

• Lead (II) Nitrate and Potassium Iodide

Pb(NO3)2 +

Lead (II) Iodide and Potassium Nitrate

KI PbI2 + KNO3 22

BELL RINGER

Predict the following products and ID the reaction type:

MgCl2 + NaOH

Practice

• Predict the product. Write and balance the following synthesis reaction equations.

Aluminum metal reacts with fluorine gas

Al(s) + F2(g) AlF33 22

Types of Reactions Lab

Types of Reactions LabYou need to make sure your tray has:

1 Test tube rack4 test tubesBox of matches10 ml Graduated cylinderWatch glassTest tube tongsCrucible tongsScoopulaWood splintPlastic spatulaMicrospatula

AND NO

GARBAGE!

• Mole Calculations•

For the Scan-Tronp. 53+54

1 – 452 – 463 – 474 – 485 – 496 – 507 – 518– 529– 5310– 5411– 5512– 5613– 57

14 – 5815 – 5916 – 6017 – 6118 – 6219 – 6320 – 6421 – 6522 – 6623 – 6724 – 6825 – 6926 – 7027 – 71

BELL RINGER

Write and balance the following:

Magnesium and oxygen react to form magnesium oxide.

HW Quiz

1. Decomposition of Aluminum oxide

2. Synthesis of sulfur trioxide

3. Combustion of Methane (CH4)

4. Sodium bromide and silver nitrate form sodium nitrate and silver bromide.

5. Balance the following:

C6H12O6 C2H5OH + CO2

Lila decided to make more baked goods for the bake sale. She used 1/8

lb less flour to make bread than to make cookies. She used ¼ lb more flour to make cookies than to make

brownies. If she used ½ lb of flour to make the bread, how much flour did

she use to make the brownies?

Are you smarter than a 5th Grader ….

StoichiometryA way to predict how many products can be made or how many reactants would be needed. You need to get the equation written correctly and balanced properly.

2H2 + O2 2H2OFor example:

You would need 2 moles of Hydrogen to make 2 moles of water

1 mole of oxygen would make 2 moles of water

If you made 6 moles of water, how much hydrogen would you need?

6 moles What would the mass of that be? 12 grams

If you had 12 moles of oxygen and 2 moles of hydrogen, how much water could you make?

2 moles of water

StoichiometryHow many moles of gold can be liberated from the decomposition of 5.2 moles of gold (III) chloride?

2 2 3

Mass

GFM

Moles ?5.20 mol

Setup mole ratio unknowncoeff

dmoleswante

givencoeff

molesgiven

..

22

20.5 xmol molx 20.5

5.20 mol

AuCl3 Au + Cl2

StoichiometryHow many grams of Chlorine can be liberated from the decomposition of 64.0g of gold(III) chloride?

2 2 3

Mass

GFM

Moles

?64.0g

303.5g/mol

.211 mol

Setup mole ratio unknowncoeff

dmoleswante

givencoeff

molesgiven

..

32

211. xmol molx 317.

.317 mol

71.0 g/mol

22.5 g

AuCl3 Au + Cl2

StoichiometryHow many grams of gold can be liberated from the decomposition of 0.50 moles of gold (III) chloride?

2 2 3

Mass

GFM

Moles

?

0.50 mol

Setup mole ratio unknowncoeff

dmoleswante

givencoeff

molesgiven

..

22

50.0 xmol molx 50.0

0.50 mol

AuCl3 Au + Cl2

197.0 g/mol

98.5 g

BELL RINGER

How many grams is 1.25 moles of Sodium hydroxide

GFM = 40Moles = 1.25 x 40 = 50 g

BELL RINGER

Gold (III) Chloride breaks into its component elements. Write the balanced equation for this

reaction.

BELL RINGER

Al + O2 Al2O3What is the total number of moles of O2 that must react

completely with 8.0 moles of Al in order to form Al2O3?

StoichiometryHow many moles of carbon dioxide are needed to produce 0.333 moles of glucose in the following reaction:

CO2 + H2O C6H12O6 + O2

Don’t panic – Balance the equation

6 6 6

Mass

GFM

Moles ? 0.333 mol

Setup mole ratiounknowncoeff

dmoleswante

givencoeff

molesgiven

..

61

333. xmol molx 00.2

2.00mol

StoichiometryWhat mass of carbon dioxide is needed to react with 54.0g of water in the following reaction:

CO2 + H2O C6H12O6 + O2

Don’t panic – Balance the equation

6 6 6

Must convert to moles – NEVER grams

Mass

GFM

Moles

? 54.0g

18.0g/mol

3.00 mol

Setup mole ratiounknowncoeff

dmoleswante

givencoeff

molesgiven

..

66

0.3 xmol

molx 0.3

3.00 mol

44.0 g/ mol

132.0 g

BELL RINGER

KClO3(s) KCl(s) + O2(g)

If you have 20.0 g of potassium chlorate, how many moles of

oxygen could you make?

Practice

6. KOH(aq) + CuSO4(aq)

Predict the products. Balance the equation

1. HCl(aq) + AgNO3(aq)

2. CaCl2(aq) + Na3PO4(aq)

3. Pb(NO3)2(aq) + BaCl2(aq)

4. FeCl3(aq) + NaOH(aq)

5. H2SO4(aq) + NaOH(aq)

HNO3(aq) + AgCl(s)

3 NaCl(aq) + Ca3(PO4)2(s) 62

PbCl2(s) + Ba(NO3)2(aq)

3 Fe(OH)3(s) + NaCl(aq)3

HOH + Na2SO4(aq) 2 2

K2SO4(aq) + Cu(OH)2(s) 2

BELL RINGER

Write the balanced equation for the decomposition of potassium chlorate.

BELL RINGER

If you wanted to make 200.0 moles of hydrogen gas from the decomposition of water, how many moles of water

would you need to start with?

Mixed Practice

• State the type, predict the products, and balance the following reactions:

1. BaCl2 + H2SO4 2. C6H12 + O2 3. Zn + CuSO4 4. Cs + Br2 5. FeCO3

To get Molecular Formula from Empirical Formula

Problem: You know a compound has an empirical formula of CN and a molecular mass of 52.0g. What is the molecular formula?

• Find the mass of the empirical formula

C – 12 N – 14 = 26

• How many times does that mass divide into the molecular mass?

52 / 26 = 2

C2N2

• Multiply that number to each element in the empirical formula

Determining Formulas from %

A student starts with 25.0 g of Barium Chloride Hydrate. The student performs the lab and has 21.4 g of anhydrous salt. What was the original

formula of the hydrated crystal?

1. You already have g so you do not have to assume 100.0 g.

2. Convert to moles

Salt –

H2O –

21.4 g

Hydrated Crystals

BaCl2 208.3 g/mol

3.6 g

÷ 208.3 g/mol

÷ 18.0 g/mol

= 0.103 mol

= 0.20 mol

Determining Formulas from %

Percent to massMass to molesDivide by small

Multiply ‘til whole

3. Divide by small

Salt

H2O

0.103 ÷ 0.103 BaCl2• ?H2O

4. Multiply ‘til whole

Do Not need to here!

Just Round

Hydrated Crystals

0.20 ÷ 0.103

= 1

= 1.94

BaCl2• 2H2O