THE MOLE

TOO SMALL TO SEE

• Because atoms are so small, it makes more sense to measure large amounts of atoms in reactions.• One mole of a substance contains the same

number of particles as atoms in 12 grams of Carbon-12

THE AVAGADRO CONSTANT

• 1 mole of a substance contains 6.022 x 1023 particles• Thats 602 200 000 000 000 000 000 000

particles!!!

EQUATION

• To calculate the moles in a substance we use the following equation:

• Moles of Atoms = Mass/Relative Atomic Mass

R.A.M.

• Relative Atomic Mass is the Ar value from the Periodic Table

QUESTION

• How many moles of atoms are there in 2.4 g of carbon?

ANSWER

• Moles of atoms = mass/R.A.M.• = 2.4/12 = 0.2 moles

THE MAGIC TRIANGLE

• Using the magic triangle we can rearrange the equation to find mass instead of moles

QUESTION

• What is the mass of 0.1 moles of Carbon Atoms?

FOR A COMPOUND

• A compound has more than one type of atom, so we have to find the Relative Formula Mass (R.F.M.)• We do this by adding the Ar of the elements in the

molecule.• So the equation then becomes:• Moles = Mass/R.F.M.

QUESTION

• How many moles are there in 8 g of copper(II) oxide (formula CuO)?• 1. Find the RFM

Cu = 64O = 16So the RFM of CuO is 80….then just follow the equation…

QUESTIONS

• How many moles of atoms are there in:1. 2 g of hydrogen2. 36 g of carbon3. 160 g of oxygen4. 14 g of nitrogen5. 0.19 g of flourine

QUESTIONS

• How many moles of molecules are there in:1. 26 g of H2O

2. 170 g of NH3

3. 1.6 g of CH4

4. O.2 g of C2H6

5. 16 g of NH4NO3