Wednesday, November 28

16-30 Compound Naming Problems: Questions?

31-40 = Homework Tonight Must complete sheet to retake Quiz 1 & 2 Thursday= Polyatomic Ions (Quiz #1 Retake) Friday= Acids (Quiz #2 Retake)

Take out Ch.7 ½ Packet from yesterday

Thursday, November 29 Turn in Compound Naming Race sheet at Front if you intend to retake quiz

Friday= Acids (Quiz #2 Retake)

Take out sheet of paper, title “Polyatomic Ions (Quiz #1 Retake)”

YOU WILL NEED CALCULATOR TODAY!

Ch. 7 Test Next Thursday!

Friday, November 30

Take out sheet of paper, title “Acids (Quiz #2 Retake)” if you are retaking quiz 2

You will need Formula Mass notes and calculator today.

Ch. 7 Test Next Thursday!

Nomenclature QUIZ 1 RETAKE• Write the compound name:

1. CaBr2

2. Na2CO3

3. Ca(OH)2• Write the formula:

4. Magnesium Carbonate5. Calcium Nitrite

Write the ion name or formula that corresponds:

6. NH4 +17. SO4 -28. Sulfite9. AsO4 -310.PO4 -3

• Write the ion name or formula that corresponds:

11. Chlorate12. ClO3 -113. OH -114. Carbonate15. ClO4 -116. NO3 -117. NO2 -1 18. Sulfate19. CN -120. SO3 -2

Nomenclature QUIZ 2 RETAKE• Write the formula name:

1. NaI

2. CaO

3. NaCl

4. Ca(OH)2

5. SO3Write the formula:

6. Sodium Fluoride

7. Potassium Sulfide

8. Iron (III) Oxide

Write the nomenclature:

9. H2SO4

10.Chloric Acid11.Hydroflouric Acid12.CH3COOH13.HClO2

14.Carbonic Acid15.Sulfuric Acid16.H2SO3

17.Nitric Acid18.HCl19.H3PO4

20.H2CO3

Chemical Formulas and CompoundsUsing Chemical Formulas

Using Chemical Formulas Chemical Formulas

A chemical formula indicates

the elements present in a compound the relative number of atoms or ions of each element present in a

compound

Chemical formulas also allow chemists to calculate a number of other characteristic values for a compound:

formula mass molar mass percentage composition

Using Chemical Formulas Formula Masses

The formula mass of any molecule, formula unit, or ion is the sum of the average atomic masses of all atoms represented in its formula

formula mass of water, H2O average atomic mass of H: 1.01 amuaverage atomic mass of O: 16.00 amu

1.01 amu2 H atoms 2.02 amu

H atom

16.00 amu1 O atom 16.00 amu

O atom

average mass of H2O molecule = 18.02 amu

Using Chemical Formulas

• Formula Masses

• The mass of any unit represented by a chemical formula (H2O, NaCl) can be referred to as the formula mass

Using Chemical Formulas

Formula Masses

• Sample Problem

• Find the formula mass of potassium chlorate, KClO3

Using Chemical Formulas

Formula Masses

• Sample Problem Solution

• The mass of a formula unit of KClO3 is found by adding the masses of one K atom, one Cl atom, and three O atoms

39.10 amu1 K atom 39.10 amu

K atom

35.45 amu1 Cl atom 35.45 amu

Cl atom

16.00 amu3 O atoms 48.00 amu

O atom

formula mass of KClO3 = 122.55 amu

The MOLE

• What is a mole?

• What is a mole of apples?

• What is a mole of carbon?

• What is a mole of H2O?

Using Chemical Formulas

• Molar Masses

• The molar mass of a substance is equal to the mass in grams of one mole, or approximately 6.022 × 1023 particles, of the substance

• The molar mass of a compound is calculated by adding the masses of the elements present in a mole of the molecules or formula units that make up the compound

Molar Masses

One mole of water molecules contains exactly two moles of H atoms and one mole of O atoms. The molar mass of water is calculated as follows

A compound’s molar mass is numerically equal to its formula mass

1.01 g H2 mol H 2.02 g H

mol H

16.00 g O1 mol O 16.00 g O

mol O

molar mass of H2O molecule = 18.02 g/mol

Using Chemical Formulas

Formula Masses

• Sample Problem

• What is the molar mass of barium nitrate, Ba(NO3)2

Using Chemical Formulas

Formula Masses

• Sample Problem Solution

• One mole of barium nitrate, contains one mole of Ba, two moles of N (1 × 2), and six moles of O (3 × 2)

137.33 g H1 mol Ba 137.33 g Ba

mol Ba

16.00 g O6 mol O 96.00 g O

mol O

14.01 g2 mol N 28.02 g N

mol N

molar mass of Ba(NO3)2 = 261.35 g/mol

Using Chemical Formulas

• Molar Mass Conversions

Molar Mass Conversions

• Sample Problem

• What is the mass in grams of 2.50 mol of oxygen gas (O2)

Using Chemical Formulas

Molar Mass Conversions

• Sample Problem Solution

• Given: 2.50 mol O2

• Unknown: mass of O2 in grams

2

22

2

32.00 g O2.50 m 80.0ol O

mol Og O

moles O2 grams O2

amount of O2 (mol) × molar mass of O2 (g/mol) = mass of O2 (g)

16.00 g O2 mol O 32.00 g

mol O O2

Using Chemical Formulas

Molar Mass Conversions

• Sample Problem

• Ibuprofen, C13H18O2, is the active ingredient in many nonprescription pain relievers. Its molar mass is 206.31 g/mol

• If the tablets in a bottle contain a total of 33g of ibuprofen, how many moles of ibuprofen are in the bottle?

• How many molecules of ibuprofen are in the bottle?

• What is the total mass in grams of carbon in 33g of ibuprofen?

Molar Mass Conversions

• Sample Problem Solution

• Given: 33g of C13H18O2, molar mass 206.31 g/mol

• Unknown: moles C13H18O2

molecules C13H18O2

total mass of C

Molar Mass Conversions• Sample Problem Solution

grams moles

13 18 2

13 18 2 13 18 213 18 2

1 mol C H Og C H O mol C H O

206.31 g C H O

moles molecules

23

13 18 2 13 18 2

6.022 10 moleculesmol C H O molecules C H O

mol

moles C13H18O2 moles C grams C

13 18 213 18 2

13 mol C 12.01 g Cmol C H O g C

mol C H O mol C

Using Chemical Formulas

Molar Mass Conversions

• Sample Problem Solution

23

2

13 18

2

2

13 18 2

6.022 10 molecules0.16mol C

9.6 10 molecules C

H Omol

H O

13 18 2

13 18 2

13 mol C 12.01 g C0.16 mol C H O

mol C H O mol C25 g C

13 18 2

13 18 213 18 2

13 18 2

1 mol C H O33 g C H O

206.31 g C H O0.16 mol C H O

Percentage Composition It is often useful to know the percentage by mass of a

particular element in a chemical compound

To find the mass percentage of an element in a compound, the following equation can be used:

The mass percentage of an element in a compound is the same regardless of the sample’s size

mass of element in sample of compound100

mass of sample of compound

% element in compound

Percentage Composition

The percentage of an element in a compound can be calculated by determining how many grams of the element are present in one mole of the compound

The percentage by mass of each element in a compound is known as the percentage composition of the compound

mass of element in 1 mol of compound100

molar mass of compound

% element in compound

Using Chemical Formulas

Molar Mass Conversions

• Sample Problem

• Find the percentage composition of copper(I) sulfide, Cu2S

Using Chemical Formulas

Molar Mass Conversions

• Sample Problem Solution

• Given: formula, Cu2S

• Unknown: percentage composition of Cu2Sformula molar mass mass percentage of each element

Molar Mass Conversions

copper(I) sulfide, Cu2S

• Sample Problem Solution

63.55 g Cu2 mol Cu 127.1 g Cu

mol Cu

32.07 g S1 mol S 32.07 g S

mol S

Molar mass of Cu2S = 159.2 g

2

127.1 g Cu100

159.2 g C79.8 u

S5% C

u

2

32.07 g S100

159.2 g C20. S

u S15%