Experience Chemistry 05.2: Moles and Molar Relationships

Lesson 5.1 & 5.2: Moles and Molar Relationships

Fill in the Blanks

What is the molar mass of the element iron? Round to two Decimal Places

Dropdown

One ​

Select answer

is equal to 6.02 ×​ 10²³, This number is also called​

Select answer

Fill in the Blanks

What is the molar mass of Copper? Round to Two Decimal Places

Fill in the Blanks

If you have 2.5 moles of nitrogen, how many atoms do you have?

Key Ideas

• Calculating Molar Mass of Compounds

• Converting between moles and Various Units

Molar Mass of Compounds

• Recall: Each element has its own molar mass

• When you have a compound made up of multiple elements, you simply add the molar masses for the total amounts of elements together

Experience Chemistry | Lesson 5.1 & 5.2

Molar Mass of Compounds Sample Problem 1

• What is the mass of Hydrogen Peroxide (H₂O₂)?

  • Step 1: Identify the amounts we have of each element

    • 2 hydrogen

    • 2 oxygen

  • Step 2: Identify the mass of all relevant atoms on the periodic table

    • Hydrogen = 1 g/mol

    • Oxygen= 16 g/mol

  • Step 3: Find our total mass by multiplying the number of each atom by its mass

    • (2 × 1) + (2 × 16) = 2 + 32

Experience Chemistry | Lesson 5.1 & 5.2

Fill in the Blanks

What is the mass of Hydrogen Peroxide (H₂O₂)?

Molar Mass of Compounds Sample Problem 2

• Phosphorous trichloride PCl₃ is used in the production of many herbicides and pesticides. What is the Molar Mass of (PCl₃)

  • Step 1: Identify the amounts we have of each element

Experience Chemistry | Lesson 5.1 & 5.2

Dropdown

Phosphorous Trichloride (PCl₃) has​

Select answer

phosphorous atom and ​

Select answer

chlorine atoms

Molar Mass of Compounds Sample Problem 2

• Phosphorous trichloride PCl₃ is used in the production of many herbicides and pesticides. What is the Molar Mass of (PCl₃)

  • Step 1: Identify the amounts we have of each element

    • 1 phosphorous

    • 3 Chlorine

  • Step 2: Identify the mass of all relevant atoms on the periodic table

Experience Chemistry | Lesson 5.1 & 5.2

Multiple Choice

What is the Molar mass of phosphorous?

• 31

• 15

• 17

• 35

Multiple Choice

What is the Molar mass of chlorine

• 31

• 15

• 17

• 35

Molar Mass of Compounds Sample Problem 2

• Phosphorous trichloride PCl₃ is used in the production of many herbicides and pesticides. What is the Molar Mass of (PCl₃)?

  • Step 1: Identify the amounts we have of each element

    • 1 phosphorous

    • 3 Chlorine

  • Step 2: Identify the mass of all relevant atoms on the periodic table

    • Phosphorous = 31 g/mol

    • Chlorine= 35 g/mol

  • Step 3: Find our total mass by multiplying the number of each atom by its mass

    • (1 × 31) + (3 × 35)

Experience Chemistry | Lesson 5.1 & 5.2

Fill in the Blanks

What is the Molar Mass of (PCl₃)

Fill in the Blanks

Sodium Bicarbonate is the chemical name for Baking Soda, and has the formula NaHCO₃. What is the molar mass of this chemical?

Fill in the Blanks

The formula for Sucrose is C₁₂H₂₂O₁₁. What is the molar mass

Avogadro's Hypothesis

• When we look at the volume of gases, we use the unit liters as our bas unit

• All Gases have the same molar volume at STP, regardless of their size

  • 1 mole=22.4 L

Experience Chemistry | Lesson 5.1 & 5.2

Molar Conversions

• Sometimes we want to change from particles to grams or grams to liters

• When we do this, we use Moles as an intermediate step for all substances

Experience Chemistry | Lesson 5.1 & 5.2

Converting With Moles sample Problem 1

• Aluminum combines with oxygen to create aluminum oxide (Al₂O₃), which protects metal from corrosion. What is the mass in grams of 9.45 mol of aluminum oxide?

  • Step 1: Identify what we need to know

Experience Chemistry | Lesson 5.1 & 5.2

Multiple Choice

To find out the mass of 9.45 moles of Al₂O₃, what do we need to know

• the molar mass of Al₂O₃

• The liters of Al₂O₃

• The number of particles of Al₂O₃

• nothing, the moles and mass are the same thing

Converting With Moles sample Problem 1

• Aluminum combines with oxygen to create aluminum oxide (Al₂O₃), which protects metal from corrosion. What is the mass in grams of 9.45 mol of aluminum oxide?

  • Step 1: Identify what we need to know

    • The molar mass of Al₂O₃

  • Step 2: Calculate the molar mass of Al₂O₃

    • 2 Aluminum, 3 Oxygen

Experience Chemistry | Lesson 5.1 & 5.2

Multiple Choice

What is the molar mass of Aluminum?

• 8

• 16

• 13

• 27

Multiple Choice

What is the molar mass of Oxygen

• 8

• 16

• 13

• 27

Converting With Moles sample Problem 1

• Aluminum combines with oxygen to create aluminum oxide (Al₂O₃), which protects metal from corrosion. What is the mass in grams of 9.45 mol of aluminum oxide?

  • Step 1: Identify what we need to know

    • The molar mass of Al₂O₃

  • Step 2: Calculate the molar mass of Al₂O₃

    • 2 Aluminum, 3 Oxygen

    • 1 Aluminum=27, 1 Oxygen= 16

    • (2 × 27) + (3×16)

Experience Chemistry | Lesson 5.1 & 5.2

Fill in the Blanks

What is the molar mass of Al₂O₃?

Converting With Moles sample Problem 1

• Aluminum combines with oxygen to create aluminum oxide (Al₂O₃), which protects metal from corrosion. What is the mass in grams of 9.45 mol of aluminum oxide?

  • Step 1: Identify what we need to know

    • The molar mass of Al₂O₃

  • Step 2: Calculate the molar mass of Al₂O₃

    • Al₂O₃ = 102 g/mol

  • Step 3: Convert your moles to grams

Experience Chemistry | Lesson 5.1 & 5.2

Fill in the Blanks

What is the mass in grams of 9.45 mol of aluminum oxide?