A Dozen Moles

Heather Berry

THE MOLE

• A chemical mole is like a dozen.• Each is a set quantity of matter.

A DOZEN

• A dozen is twelve of any object, such as eggs or cookies.

• So, in reverse, 12 symbols equals a dozen symbols.

A DOZEN AND MOLES

Dozen12 of an object

Can be divided (i.e. half a dozen = 6)

Can be multiplied (i.e. two dozen = 24)

Mole6.02 x 1023 atoms of an

elementCan be divided (i.e. half

a mole = 3.01 x 1023)

Can be multiplied (i.e. 12.04 x 1023)

BREAK IT DOWN

• How many eggs are there in 0.75 dozen?• .75 dz x 12 eggs/1 dz = .75 x 12 = 9 eggs• How many particles are there in 0.5 moles?• .5 moles x 6.02 x 1023 particles/1mole= 3.01 x

1023 particles

BREAK IT DOWN SOME MORE!

• How many dozen does 54 eggs make?• 54 eggs x 1 dz/12 eggs = 54/12= 4.5 dz

• How many moles in 2.11 x 1024 particles?• 2.11 x 1024 particles x 1mole / 6.02 x 1023

particles = 2.11 x 1024 / 6.02 x 1023 = 3.5 moles.

Representative Particles

• Atom

• Molecule

• Ion

• Formula Unit

• N , C

• N2, H2O, C12H22O11

• Ca+2, Cl-1

• CaF2, NaCl, CaCO3

6.02 x 1023

# of particles in one mole

6.02 x 1023

6.02 x 1023

6.02 x 1023

PRACTICE

• Name the representative particle of each substance.

A. Oxygen gasB. Sodium sulfideC. Sulfur dioxideD. Potassium

A. Molecule (O2)

B. Formula Unit (Na2S)

C. Molecule (SO2)

D. Atom (K)

PRACTICE

• Which contains more molecules: 1 mol H2O2, 1 mol C2H6, or 1 mol CO?

• All contain 6.02 x 1023 molecules • Which contains more atoms: 1 mol H2O2, 1

mol C2H6, or 1 mol CO?

• 1 mol C2H6

Determining the number without COUNTING!

• How many beans are in the bag?

EXPLORE:DETERMINING NUMBER

WITHOUT COUNTINGQuestion: How many beans are in the bag? You

CANNOT open the bag! _________________________

• Assignment: • Develop an experimental procedure for determining

the number of beans in the bag without opening it.• List the materials you will need to carry out your

plan.• Have your plan approved by your teacher. • Carry out your plan, making notes of any changes

made to your original plan.

CONCLUSION

• How many beans are in the bag? Explain how you determine the number.

• What do chemists mean by the phrase, counting by weighing�?

ELABORATE

• Mole Conversion Homework Practice.• Essential Question:• How do you determine the mass and number of

atoms of carbon that can be marked on a piece of paper in 2 minutes?

ELABORATE

• Making a Mole of Pencil Marks

• Procedure:• Read the entire procedure and make a table to

record collected data.• Measure and record the mass of a piece of paper.• Place as many graphite (carbon) pencils marks as

you can on your piece of pre-massed paper.• Measure and record the mass of the paper with the

pencil marks.

ELABORATE

• Calculations: You MUST show ALL you work.

• Calculate the mass of graphite (carbon) you placed on your piece of paper in two minutes.

• Calculate the number of carbon atoms you placed on your paper in two minutes.

• Calculate how many minutes it would take you to place a mole of carbon atoms on your piece of paper.

5. Draw Conclusions about Target

• Both words mean a specific quantity of an item.

• Each can be multiplied or divided by any number to establish a ratio to the whole.

6. Indicate Where Analogy Breaks Down

• While a dozen only indicates 12, a mole can indicate numerous equalities.

• In addition to 6.02 x 1023 atoms, a mole is also the same as having the molar mass of a substance, or 22.4L of the substance at standard temperature and pressure.

• Furthermore, the molar mass changes by element/compound where as a dozen is always twelve.