What are different ways (measurements) or places to

buy apples?

Mole

• Equal toEqual to 6.02 x 1023 things (Avogadro’s Number)

• DefinedDefined to be the number of carbon-12 atoms found in exactly 12.000 g of carbon-12

• DeterminedDetermined through various experiments and calculations in the 20th century.

Which is more useful for calculating teacher/student ratio

• There are 11756 kg of students in the freshman class

• There are 190 students in the freshman class

The concept of “the mole” allows us to compare quantities of items

that have different masses

Like the apple analogy•We can quantify chemical substances in 4 different ways …

1.Particles2.Moles (Number of Particles)3.Volume4.Mass

•We will convert between these 4 ways of quantifying substances

Molar Mass

VOLUME

MOLE

MASS

PARTICLES

VOLUME

MOLE

MASS

PARTICLES

C6

Carbon

12.011 Atomic Mass:1 atom of carbon has a mass of 12.011 amu

Molar Mass:1 mole of carbon (6.02 x 1023 atoms) has a mass of 12.011 g

The Molar Mass is

• The conversion factor we will use to convert between moles and mass

• It is the mass (amount of matter) of one mole of a substance

• We can use the periodic table to help us determine the molar mass

• What is the molar mass of titanium?

• sulfur?

• chlorine?

• water?

• sodium sulfate, Na2SO4?

• calcium nitrate, Ca(NO3)2?

A sample of iron has a mass of 24.5 g.

• Do we have a mole of iron? How do you know?

• What mass would a 1 mole sample of sugar, C12H22O11, have?

A sample of iron has a mass of 24.5 g.

• Do we have a mole of iron?

• How many moles of iron do we have?

Convert1. 50.0 g of silver to moles

2. 34.5 g of sulfur dioxide to moles

3. 0.056 moles of sodium phosphate to grams

Find the molar mass of silver, sulfur dioxide, and sodium phosphate … then

Convert

• A) 15.6 grams of calcium nitrate, Ca(NO3)2, to moles

• B) 0.050 moles of sulfur dichloride, SCl2, to grams

Convert

• A) 10.0 grams of Cu(HCO3)2 to moles

• B) 2.050 moles of Al2O3, to grams

• How many things are in a pair?

• In a dozen?

• In a mole?

6.02 x 1023

VOLUME

MOLE

MASS

PARTICLES

1 mole of any substance contains 6.02x1023 particles (Avogadro’s #)

• 1 mole of carbon contains 6.02x1023

carbon atoms

• 1 mole of carbon tetrachloride contains 6.02x1023 carbon tetrachloride molecules

• 1 mole of sodium carbonate contains 6.02x1023 sodium carbonate formula units

1 mole of any substance contains 6.02x1023 particles (Avogadro’s #)

• Atom –

• Molecule –

• Formula Unit -

Pure element (C, S, Na)

Molecular Compound(CCl4,H2O,N2)

Ionic Compound (NaCl, Cu2S)

Convert

• 1.59 x 1024 oxygen molecules to moles

• 0.50 moles of potassium to atoms

• 20.56 grams of sodium chloride to formula units

Convert

• 3.0 grams of magnesium chloride to moles

• 0.34 moles of hexane to molecules

• 3.4 x1020 formula units of calcium hydroxide to mass

Do now:

• What are other words that can be used to describe “particles” in chemistry?

• Explain how to (step-by-step) convert from

a)Moles to particles

b)Particles to moles

• Does the identity of the substance affect how you solve the problem?

22.4 L if a gas at 0ºC

and 1 atm(STP)

VOLUME

MOLE

MASS

PARTICLES

Try these!

• What is the volume occupied by 3.00 moles of sulfur dioxide gas, at STP?

• How many moles of gas are in a balloon whose volume is 1.5 L, at STP?

22.4 L if a gas at 0ºC

and 1 atm(STP)

(atoms, molecules,

formula units)VOLUME

MOLE

MASS

PARTICLES

Molar Mass

6.02 x 10 23

Do Now:1. What are the conversion factors used to

convert from mole to

a) Mass?

b) Particles? (Atoms, Molecules, Formula Units)

c) Volume?

2. If the given is in moles, how do you use the conversion factors above?

3. If the answer needs to be found in moles, how do you use the conversion factors above?

Do Now:1. What is the first step in a mole problem?

2. What is the second step in a mole problem, to help you keep focus?

3. What are the three possible conversions into or out of mole?

4. How do you know if the problem is one step or multistep?

5. Convert ….

• 3.50 moles of sodium nitrate to mass• 4.90 L of nitrogen gas at STP to mole• 5.67 grams of Cu to atoms

Try these!• A reaction produces 65.30 g of

calcium carbonate. How many formula units of calcium carbonate is this?

• A 3.0 L balloon holds CO gas at STP. How many molecules of gas are in the balloon.

• In the transfer of solids, 0.025 g of copper was left in the beaker. How many atoms of copper is this?

DO NOW!

• What is the percent composition of this class?

• Experimental: Find the percent composition if

• A) A sample contains 0.16 grams of hydrogen and 2.3 grams of oxygen.

• B) A sample contains 25.0 g of carbon, 3.9 g of hydrogen, and 30.8 of oxygen.

• Theoretical:

A)Find the percent composition of water.

B)Find the percent composition of glucose, C6H12O6

C)How many grams of carbon are there in a 25.0 g sample of glucose.

What is theWhat is the

Empirical Formula?Empirical Formula?Molecular Formula?Molecular Formula?

The actual formula for The actual formula for glucose is Cglucose is C66HH1212OO66. What . What

is the empirical formula?is the empirical formula?

What is the empirical What is the empirical formula for water?formula for water?

Formula Percent CompositionFormula Percent Composition

Percent Composition Formula

Determine the empirical formula Determine the empirical formula for…for…

The mineral cassiterite.The mineral cassiterite.Chemical analysis of the mineral Chemical analysis of the mineral

cassiterite shows that this cassiterite shows that this compound contains 78.8% tin, by compound contains 78.8% tin, by mass, and the rest is oxygen.mass, and the rest is oxygen.

A white powder is analyzed A white powder is analyzed and found to contain 2.180 g and found to contain 2.180 g of phosphorus and 2.820 g of of phosphorus and 2.820 g of oxygen. What is the empirical oxygen. What is the empirical

formula for this compound?formula for this compound?

Do NOwDo NOw What is the difference between the empircal What is the difference between the empircal

and molecular formulas?and molecular formulas?

Provide the empirical formulas for:Provide the empirical formulas for:

HH22OO22, CaSO, CaSO44, C, C33HH66

What steps must you take to find the empirical What steps must you take to find the empirical formula provided with the composition of the formula provided with the composition of the compound…either percentages or masses?compound…either percentages or masses?

11The compound methyl benzoate, The compound methyl benzoate, used in the manufacture of perfumes, used in the manufacture of perfumes, consists of 70.58% C, 5.93% H and consists of 70.58% C, 5.93% H and 23.49% O, by mass. Also, by 23.49% O, by mass. Also, by experiment the molar mass is found experiment the molar mass is found to be 136 g/mol. What are the to be 136 g/mol. What are the empirical and molecular formulas of empirical and molecular formulas of methyl benzoate?methyl benzoate?

The compound methyl benzoate, The compound methyl benzoate, used in the manufacture of perfumes, used in the manufacture of perfumes, consists of 70.58% C, 5.93% H and consists of 70.58% C, 5.93% H and 23.49% O, by mass. 23.49% O, by mass. Also, by Also, by experiment the molar mass is experiment the molar mass is found to be 136 g/mol.found to be 136 g/mol. What are What are the empirical and molecular formulas the empirical and molecular formulas of methyl benzoate?of methyl benzoate?

What is the empirical formula of a What is the empirical formula of a compound that is 66.0% Ca and compound that is 66.0% Ca and 34.0% P?34.0% P?