Chemical Quantities

Scientists are interested in determining how much product can be produced for a given amount of reactants.

How many grams of water are produced when 20.0 g of Hreacts?

• Determine how much of something by counting, measuring mass or volume.•Use a unit called the mole to measure the amount of a substance.

Mole•6.02 x 1023 representative particles(atoms,molecules,formula units)

• Called Avogadro’s Number

Representative Particle•Atom, molecule, formula unit, or ion• Water— H20 Molecule• Chlorine— Cl2 Molecule (diatomic)• Sodium chloride— NaCI formula unit

How many moles in 2.41 x 1024

formula units of NaCI?

2.41 x 1024 fo.units 1 mole______

6.O2 x 1023 fo.units

= 4.00 moles

Practice• How many moles in 9.03 x 1024

atoms Hg? 9.03x1O24atoms 1 mole_____ 1 6.O2xlO23atoms= 15.0 moles

• How many atoms in 4.50 moles Ca?

4.50 moles 6.02x1023 atoms 1 1mole

=2.709 x IO24 atoms =2.71 x 1024 atoms

• How many molecules in 100.0 moles C02? 100.0 moles 6.02x1023molecules

1 1 mole

=6.020 x 1025 molecules

• How many atoms in 1.00 mole sucrose (C12H22O11)?

1 molecule = 12 + 22 + 11 atoms = 45 atoms

1.00mol 6.02x1O23molecules 45atoms1 I mole 1 molecule

= 2.71 x 1025 atoms

• How many atoms of C are in 2.0 mol C12H22O11? 2.0mol 6.02x1023molecules 12atoms

1 1 mol 1molecule

= 1.4 x 1025 atoms C

• How many atoms of H are in 2.00mol C12H22O11? 2.00mol 6.02x1O23molecules 22atoms

1 1mol 1molecule

=2.65 x 1025 atoms H

• How many atoms of 0 are in 3.65 mol C12H22O11? 3.65mol 6.02x 1O23moIecuIes 11atoms

1 1mol 1molecule

=2.42 x 1025 atoms O

Gram Atomic Mass• Called GAM• Mass of one mole of an element• Get GAM off periodic table• C- 12.0 g• O- 16.0 g Round to 1• Cu- 63.5g decimal place

• Remember: I atom has a massin amu

C= 12.0 amu 0= 16.0 amuCu= 63.5 amu• The GAM of any element contains the

same number of atoms- 1 mol or 6.02 x 1023 atoms

Find the mass of 1 mol of a compound

• Start with the formula• Tells which atoms and how many

NH31molecule = 1 N atom 14.0 amu 3 H atoms 3(1.0) amuImolecule NH3 = 17.O amu

If you do the same thing using GAM- get gram molecular mass (gmm)1 N atom 14.Og3 H atoms 3(1.0) 3.0g

17.Og1mole NH3 = 17.Og and contains6.02 x 1023 molecules of NH3

PracticeWhat is the mass of one mole of:

CO2

1 C atom 12.0g2 O atoms 2(16.0) 32.0g

44.0g

NaOH1 Na atom 23.0 g1 O atom 16.0 g1 H atom 1.0g

40.0g

Ba(N03)2

1 Ba atom 137.3 g2 N atoms 2(14.0) 28.0 g6 O atoms 6(16.0) 96.0 g

261.3 g

For ionic compounds findGram formula mass (gfm)• NaCI

1 Na atom 23.0 g1 Cl atom 35.5 g

58.5 gHow many formula units are in

58.5g NaCI?6.02 x 1023 formula units