Chemical calculations

Question 1

What is the definition of relative atomic mass?

Answer 1

The weighted average of the masses of an element that it includes all the isotopes relative to 1/12 of the mass of a carbon-12 atom.

Question 2

What is the definition of relative isotopic mass?

Answer 2

The mass of an isotope relative to 1/12 of the mass of a carbon-12 atom.

Question 3

What is the definition of relative molecular mass?

Answer 3

The weighted average of the masses of the molecules relative to 1/12 of the mass of a carbon-12 atom.

Question 4

What is the definition of molar mass?

Answer 4

The sum of all the relative atomic masses of all the atoms present within the substance, divided by the amount of the substance.

Question 5

What is Avogadro’s number?

Answer 5

Its the same number of particles as there are atoms in 12g of C-12 (6.02x10^23)

Question 6

What formula is used to calculate moles from the Mr and mass of a substance?

Answer 6

moles = mass/Mr