Model 1: The Mole, a way of counting numbers of atoms and molecules
1 dozen = 12 objects = 1.2 x 101 objects
1 mole = 602,200,000,000,000,000,000,000 objects = 6.022 x 1023 objects
Hydrogen has 1 protons and an average atomic mass of 1.008 amu or 1.008 grams / mol.
Carbon has 6 protons and an average atomic mass of 12.011 amu or 12.011 grams / mol.
Oxygen has 8 protons and an average atomic mass of 15.999 amu or 15.999 grams / mol.
Aluminum has 13 protons and an average atomic mass of 26.982 amu or 26.982 grams / mol.
Critical Thinking Questions:
- How many eggs are in one dozen eggs?
- How many oranges are in one dozen oranges?
- How does the identity of the object affect the number of items in dozen?
- How many eggs are in 2 dozen eggs?
- How many eggs are in 117.25 dozen eggs?
- If you had 154,589 individual eggs, how many dozen eggs would you have?
- Using a grammatically correct English sentence, describe how to convert any number of dozen objects to a number of individual objects (i.e. 117.25 dozen eggs to number of individual eggs).
- If a large egg weighs 2 ounces, what is the mass in grams of one dozen eggs?
- If a watermelon weighs 10 pounds, what is the mass in grams of one dozen watermelons?
- How does the mass of a dozen objects depend on the mass of the individual object?
- How many carbon atoms are in one mole of carbon?
- What is the mass, in grams, of one mole of carbon atoms?
- How many aluminum atoms are in one mole of aluminum?
- What is the mass, in grams, of one mole of aluminum?
- What is the mass, in grams, of 117.25 moles of aluminum?
- Using a grammatically correct English sentence, explain how to calculate the mass of a certain number of moles of a certain substance.
Model 2: Converting between Mass and Amount of Substance
| Chemical Formula | Structure | 3D structure |
| CH4methane |
Critical Thinking Questions:
- If a watermelon has 400 seeds in it, how many seeds would you find in one dozen watermelons? (express your answer in scientific notation)
- If a watermelon seed has a mass of 0.25 g, what is the mass of the seeds in one dozen watermelons?
- How many carbon atoms are in one methane (CH4) molecule?
- How many moles of carbon atoms are in one mole of methane (CH4) molecules?
- What is the mass, in grams, of the carbon atoms in one mole of methane (CH4) molecules?
- How many hydrogen atoms are in one methane (CH4) molecule?
- How many moles of hydrogen atoms are in one mole of methane (CH4) molecules?
- What is the mass, in grams, of the hydrogen atoms in one mole of methane (CH4) molecules?
- What is the total mass of one mole of methane molecules?
- If you had 117.25 grams of methane, how many moles of methane would you have?
- Convert the previous number of moles of methane to number of molecules of methane.
- Using a grammatically correct English sentence, explain how to convert grams of a substance into number of molecules of substance.
Exercises:
- What is the mass of 1.00 moles of Iron?
- What is the mass of 8.52 moles of Iron?
- How many atoms are in 5.66 g of Iron?
- How many water molecules (H2O
- ) are in 8.69 mg of water?
Challenge Problem:
- An aluminum sphere contains 6.23 x 1024 atoms. What is the radius of the sphere? (The density of aluminum is 2.70 g/cm3)




