*Do Now Molar Mass

(1)

*Do Now Molar Mass

• Determine the mass of 5 moles of C₁₂H₂₂O₁₁ (sucrose) using molar masses from the

periodic table.

Learning Target

Students will be able to explain molar mass and Avogadro’s number and perform calculations.

(2)

*Do Now - Molar Mass

• Determine the mass of 5.00 moles of

C₁₂H₂₂O₁₁(sucrose) using molar masses from the periodic table.

(12 X 12.01g) + (22 X 1.01g) + (11 X 16.00g) = 342.34g

5.00 mol X 342.24 g = 1711.7 g 1 mol

Learning Target

(3)

Conservation of Mass

How would the mass

of this assembled

barbell compare

with the mass of the

unassembled barbell?

How do you think the combined mass of one

carbon atom and two oxygen atoms compares with the mass of a molecule of carbon dioxide (CO₂)?

Learning Target

(4)

Mass of a Backpack

• The mass of your backpack is the sum of the mass of the pack plus the

masses of the textbooks, notebooks, pencils, lunch, and miscellaneous items you put into it.

• You could find its mass by

determining the mass of each item separately and adding them

together.

Similarly, the mass of a mole of a compound equals the sum of the masses of every particle that makes up the compound.

Learning Target

(5)

Molar mass of SO

₃

Sulfur trioxide is composed of one atom of sulfur and three atoms of oxygen.

1 mol SO3= 1 mol S atoms + 3 mol O atoms

– Using the periodic table, the mass of one mole of each element present in SO3can be determined.

Sulfur = 32.06 g/mol Oxygen = 15.99 g/mol

=

1 x 32.06g/mol + 3 x 15.99g/mol = 80.06 g/mol

Learning Target

(6)

Counting by Measuring Mass

Think how can you measure 1 mole of water without counting individual H₂O molecules.

Learning Target

(7)

The Mole & Volume

• Equal volumes of gases at the same

temperature and pressure have the same number of particles

• At __STP__ (Standard Temperature &

Pressure), which is 0^oC and 1 atmosphere

– 1 mole of a gas has a Volume = 22.4 L

– So, a Volume of 22.4 L of any gas at STP contains 6.02X10²³ particles

– This is called the molar volume of gas, since it is 1 mole of particles of a gas

Learning Target

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Moles and Gases

•

Learning Target

(9)

Calculating the Volume of a Gas Using Moles

• 22.4 L = 1 mole at STP can be used as a conversion factor

• *If you have 0.60 mol of sulfur dioxide (SO₂) at STP, determine the volume in Liters it will take up.

Learning Target

(10)

Calculating The Volume of a Gas

• *If you have 0.60 mol of sulfur dioxide (SO₂) at STP, determine the volume in Liters it will take up.

0.60 mol X 22.4 L = 13 L SO₂ 1 mol

Learning Target

(11)

Calculating Molar Mass and Density

• Different gasses have different densities

– They have different masses (p, n, e) even though they have the same Volume

• Gasses have their densities measured in g/L

• The molar volume of 22.4 L/mol can be used to calculate the molar volume of a gas at STP

Learning Target

(12)

Using Molar Mass with Density

• The density of a gas at STP is 1.964 g/L. What is the molar mass of the compound?

Learning Target

(13)

Using Molar Mass with Density

• The density of a gas at STP is 1.964 g/L. What is the molar mass of the compound?

1.964 g X 22.4 L = 44.0 g/mol 1 L 1 mol

Learning Target

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Learning Target

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Learning Target

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Molar mass of H

₂

O

To find the molar mass of a compound, find the number of grams of each element in one mole of the compound. Then add the masses of

elements in the compound.

*What is the molar mass of water (H2O)?

Learning Target

(17)

*Molar Mass

Determine the molar mass of C₈H₁₈(octane) using molar masses from periodic table.

Learning Target

(18)

*Do Now

You need one mole of table salt (NaCl) for an experiment.

a. List the steps you take to measure out one mole of table salt (NaCl)

b. Is it possible to count Avogadro’s number of salt particles individually?

Learning Target