Quantitative chemistry

Conservation of mass definition

No atoms are made or lost during a chemical reaction. The mass before the reaction must equal the mass after a reaction IN A CLOSED SYSTEM

Closed system definition

container which no chemicals can escape e.g. a sealed bottle

Relative formula mass (Mr) definition

Sum of relative atomic masses from periodic table

Balanced equation definition

When the sum of the Mr on the left equals the sum of the Mr on the right

Limiting reactant definition

The reaction which runs out first

concentration equation

mass (g) = conc. (g/dm³) x volume (dm³)

mole definition

The number of particles needed to make the mass equal the atomic mass

Avogadro’s constant

6.022 × 10²³ particles in 1 mole

mole equation

mass = moles x Mr