Moles and Mole Conversions
Instructions:
- Explore: Look through this presentation for key ideas and examples
- Read: Chapter 3-2 in your textbook.
- Start working on Stuidy Guide, due on 11/21
Resources:
Click here for Textbook
Click here for study Guide ( due 11/21)
4.1 Lesson (accelerate)
3.2 — The Mole and Atomic Mass
The mole is the fundamental unit used to measure the amount of a substance. It connects the microscopic world of atoms and molecules to the macroscopic quantities we can measure in the lab.s.
- 1 mole = 6.022 × 10²³ particles (atoms, molecules, ions)
- Developed by Amedeo Avogadro to relate gas volume and particle number
- This number allows us to convert between microscopic (atoms) and macroscopic (grams) quantities.
This relationship allows chemists to count atoms using a balance instead of direct observation.
Visualizing the Mole
The magnitude of 6.022 × 10²³ is enormous — one mole of sand grains would cover the Earth with a layer several miles deep! This huge number compensates for how incredibly small atoms are.
For perspective:
- 1 mole of carbon = 6.022 × 10²³ C atoms = 12.00 g
- 1 mole of helium = 6.022 × 10²³ He atoms = 4.00 g
- 1 mole of iron = 6.022 × 10²³ Fe atoms = 55.85 g
The mass of one atom of carbon can be found by dividing 12 g by Avogadro’s number.
Intro to Moles Video
Relationship Between Atomic Mass and Molar Mass
Each element’s atomic mass (in amu) is numerically equal to the molar mass of that element (in g/mol). For example:
- Carbon: 12.01 amu → 12.01 g/mol
- Sodium: 22.99 amu → 22.99 g/mol
- Phosphorus: 30.97 amu → 30.97 g/mol
This direct relationship allows you to move between atomic-scale mass and measurable grams using the mole as a bridge.
1 amu = (1 g) / (6.022 × 10²³) = 1.66 × 10⁻²⁴ g
Periodic Table
Molar Mass from Molecular Mass
The molar mass of a compound (in g/mol) is numerically equal to its molecular mass (in amu). For instance:
- Water: 18.02 amu → 18.02 g/mol
- SO₂: 64.07 amu → 64.07 g/mol
- Caffeine: 194.20 amu → 194.20 g/mol
1 mole of H₂O weighs 18.02 g and contains 6.022 × 10²³ molecules.
This relationship connects atomic-scale mass to lab-scale measurements.
Example 1: Converting Grams to Moles
Helium (He) is used in balloons and research applications. How many moles are in 6.46 g of He? Step 1: Identify the molar mass of He = 4.003 g/mol Step 2: Use the conversion factor (1 mol / 4.003 g): (6.46 g) × (1 mol / 4.003 g) = 1.61 mol He Because the given mass is greater than 4.003 g, the result should be greater than 1 mol. number.
Converting between Gram and Moles
Example 2: Converting Moles to Grams
Zinc (Zn) is used in making brass and in galvanizing steel. How many grams are in 0.356 mol of Zn?
Molar mass of Zn = 65.39 g/mol
Calculation:
(0.356 mol) × (65.39 g / 1 mol) = 23.3 g Zn
Since this is less than one mole, the mass is less than 65.39 g, which makes sense.
Converting Between Moles, Atoms, and Molecules
Example 3: The Mass of a Single Molecule
The C₆₀ molecule (buckminsterfullerene) contains 60 carbon atoms. What is the mass of one C₆₀ molecule?
Step 1: One mole of carbon = 12.011 g = 6.022 × 10²³ atoms.
Step 2: Mass of one C₆₀ molecule = (60 × 12.011 g) / (6.022 × 10²³) =1.20 × 10⁻²⁰ g Each C₆₀ molecule is extremely light — trillions are needed for even a milligram sample!
Example 4: Counting Atoms in Compounds
How many hydrogen atoms are in 25.6 g of urea [(NH₂)₂CO]?
- Molar mass of urea = 60.06 g/mol
- Convert grams to moles: (25.6 g) × (1 mol / 60.06 g) = 0.426 mol urea
- Each urea molecule has 4 H atoms → 4 mol H per mol urea
- (0.426 mol urea) × (4 mol H / 1 mol urea) × (6.022 × 10²³ atoms/mol) = 1.03 × 10²⁴ H atoms
Lets Practice!
Hints:
- Calculate molecular mass using the periodic table.
- Remember: molar mass (g/mol) = molecular mass (amu).
- Use Avogadro’s number to convert moles to particles or atoms.
Lets Practice!
Hints:
- Calculate molecular mass using the periodic table.
- Remember: molar mass (g/mol) = molecular mass (amu).
- Use Avogadro’s number to convert moles to particles or atoms.
Moles and Mole Conversions
Nicholas Espalin
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Transcript
Moles and Mole Conversions
Instructions:
Resources:
Click here for Textbook
Click here for study Guide ( due 11/21)
4.1 Lesson (accelerate)
3.2 — The Mole and Atomic Mass
The mole is the fundamental unit used to measure the amount of a substance. It connects the microscopic world of atoms and molecules to the macroscopic quantities we can measure in the lab.s.
- 1 mole = 6.022 × 10²³ particles (atoms, molecules, ions)
- Developed by Amedeo Avogadro to relate gas volume and particle number
- This number allows us to convert between microscopic (atoms) and macroscopic (grams) quantities.
This relationship allows chemists to count atoms using a balance instead of direct observation.Visualizing the Mole
The magnitude of 6.022 × 10²³ is enormous — one mole of sand grains would cover the Earth with a layer several miles deep! This huge number compensates for how incredibly small atoms are. For perspective:
- 1 mole of carbon = 6.022 × 10²³ C atoms = 12.00 g
- 1 mole of helium = 6.022 × 10²³ He atoms = 4.00 g
- 1 mole of iron = 6.022 × 10²³ Fe atoms = 55.85 g
The mass of one atom of carbon can be found by dividing 12 g by Avogadro’s number.Intro to Moles Video
Relationship Between Atomic Mass and Molar Mass
Each element’s atomic mass (in amu) is numerically equal to the molar mass of that element (in g/mol). For example:
- Carbon: 12.01 amu → 12.01 g/mol
- Sodium: 22.99 amu → 22.99 g/mol
- Phosphorus: 30.97 amu → 30.97 g/mol
This direct relationship allows you to move between atomic-scale mass and measurable grams using the mole as a bridge. 1 amu = (1 g) / (6.022 × 10²³) = 1.66 × 10⁻²⁴ gPeriodic Table
Molar Mass from Molecular Mass
The molar mass of a compound (in g/mol) is numerically equal to its molecular mass (in amu). For instance:
- Water: 18.02 amu → 18.02 g/mol
- SO₂: 64.07 amu → 64.07 g/mol
- Caffeine: 194.20 amu → 194.20 g/mol
1 mole of H₂O weighs 18.02 g and contains 6.022 × 10²³ molecules. This relationship connects atomic-scale mass to lab-scale measurements.Example 1: Converting Grams to Moles
Helium (He) is used in balloons and research applications. How many moles are in 6.46 g of He? Step 1: Identify the molar mass of He = 4.003 g/mol Step 2: Use the conversion factor (1 mol / 4.003 g): (6.46 g) × (1 mol / 4.003 g) = 1.61 mol He Because the given mass is greater than 4.003 g, the result should be greater than 1 mol. number.
Converting between Gram and Moles
Example 2: Converting Moles to Grams
Zinc (Zn) is used in making brass and in galvanizing steel. How many grams are in 0.356 mol of Zn? Molar mass of Zn = 65.39 g/mol Calculation: (0.356 mol) × (65.39 g / 1 mol) = 23.3 g Zn Since this is less than one mole, the mass is less than 65.39 g, which makes sense.
Converting Between Moles, Atoms, and Molecules
Example 3: The Mass of a Single Molecule
The C₆₀ molecule (buckminsterfullerene) contains 60 carbon atoms. What is the mass of one C₆₀ molecule? Step 1: One mole of carbon = 12.011 g = 6.022 × 10²³ atoms. Step 2: Mass of one C₆₀ molecule = (60 × 12.011 g) / (6.022 × 10²³) =1.20 × 10⁻²⁰ g Each C₆₀ molecule is extremely light — trillions are needed for even a milligram sample!
Example 4: Counting Atoms in Compounds
How many hydrogen atoms are in 25.6 g of urea [(NH₂)₂CO]?
Lets Practice!
Hints:
Lets Practice!
Hints: