Amount of Substance

Question 1

What is the formula that links moles, mass and Mr?

Answer 1

Moles (mol) = Mass (g) / Mr
Mass (g) = moles (mol) × Mr

Question 2

What is Avogadro’s constant? What does it mean?

Answer 2

6.022 × 10²³

The number of units in 1 mole of any substance

Question 3

What is the formula that links concentration, volume and moles?

Answer 3

Concentration (mol dm-³ / g dm³) = Moles (mol) / Volume (cm³ / dm³)
Moles = Concentration x Volume
Volume = Moles / Concentration

Question 4

How do you find the mass of 1 atom using Avogadro’s constant?

Answer 4

Relative atomic mass / 6.022 × 10²³