Quantitative chemistry

Define relative atomic mass

The average mass of all of the isotopes of that element

Relative atomic mass symbol

Ar

What is the symbol for relative formula mass?

Mr

Formula for moles

moles=mass/Mr

What is a mole?

1 mole of a substance is the amount of that substance that contains 6.02×10²³ particles (e.g atoms or molecules)

What is Avogadro’s constant?

The number of particles in 1 mole of a given substance. The value of the constant is 6.02×10²³

e.g 1 mole of carbon is exactly 6.02×10²³ atoms of carbon, 1 mole of hydrochloric acid is exactly 6.02×10²³ molecules of HCl

What is molecular ratio?

The ratio between the moles of different reactants and products in a balanced equation

What is the law of conservation of mass?

No atoms are lost or made during a chemical reaction

Will the mass change during a chemical reaction?

The overall mass of the products will be exactly the same as the overall mass of the reactants

Why might the total mass appear to change during a chemical reaction?

-Gases from the air may react with the chemicals in the beaker, increasing mass

-Gaseous products may escape from the beaker into the air, decreasing mass

-Some chemicals may be lost via spilling or evaporation, decreasing mass

What is a limiting reactant?

The reactant that gets all used up, so limits how much product can be made

What is a reactant in excess?

There is more that is needed, so there is some left over at the end of the reaction

concentration of a solution formula

concentration = mass/volume

How many cm³ are in a dm³?

1000

how many litres are in 1 dm³?

1 dm³ = 1 litre