SCH3U - Unit 3

n

amount (mol)

N

amount (particles)

Mol → particles

6.02×10²³/mol

Particles → mol

mol/6.02×10²³

Mol → mass (g)

molar mass/mol

Mass (g) → mol

mol/molar mass

Mass percent

grams of element/grams of compound x100%

Calculating percent composition from a formula

1. Find molar mass of compound

2. Assume a 1mol sample and find mass percent of each element

Hydrate

Ionic compound that has water molecules bound to it in a fixed ratio

Ionic compound

non metal + metal

Molecular compound

non metal + non metal

Determining the formula of a hydrate

1. Find the amount of water

2. Find the molar mass of water

3. Find the amount of anhydrous salt

4. Compare moles of water from the anhydrous salt to moles of water of the hydrate by dividing by the number of moles of the anhydrous salt (ratio).

Mole ratio

Conversion factor that allows you to convert from one “type” of mole to another

Mole → mole conversion

Moles of substance A x mole ratio = moles of substance B

Mass → mass conversion

1. Convert the mass of what has been given into moles using its molar mass

2. Convert the moles of what has been given to the moles of what is required by using the mole ratio

3. Convert the moles of what is required to the mass of what is required by using its molar mass

Reactant ←→ product steps

1. mA → nA using MA

2. nA → nB using mole ratio

3. nB → mB using MB