UF calculations

definition of relative atomic mass

• average mass of an atom of an element, compared to the mass of a carbon atom (12)

• relative atomic mass found in periodic table.

relative formula mass

atomic masses for each of the elements in the compound, added together

percentage of an element in a compound

% = RAM/RFM of compound x 100

mr, mass and moles

mass = mr x mol

(triangle)

percentage yield

% yield = (actual yield/expected yield) x 100

empirical formula

simplest whole number ratio between atoms…

1. number of moles

2. divide by smallest mole

3. calculate ratio

water of crystallisation

1. mass

2. moles

3. ratio

limiting reagents

1. balance equation

2. moles of reactant

3. ration of reactants (choose one reactant and work out number of moles of other reactants needed.)

4. identify limiting reagent

rate

change in reactant/time

energy transferred

specific heat capacity x mass of water x temp. difference

enthalpy value/energy change

energy transferred/moles fuel burnt

moles, volume, and concentration

mol = volume x concentration