Physical - Amount Of Substance

Question 1

Define relative atomic mass.

Answer 1

The average mass of all the isotopes of an element, with abundance taken into account, relative to 1/12th the mass of an atom of carbon-12.

Question 2

Give the equation for relative atomic mass using carbon-12

Answer 2

Relative atomic mass Ar = average mass of one atom of an element / (1/12) mass carbon-12

Question 3

Define Relative Molecular mass (Mr)

Answer 3

The average mass of a molecule compared to 1/12 the relative atomic mass of an atom of carbon-12.

Question 4

What number is a mole?

Answer 4

Avogadro’s constant - 6.022 x 10^23