Define the term relative molecular mass.

Relative molecular mass is the average mass of a molecule compared to 112\frac{1}{12}th of an atom of carbon-12.


Relative molecular mass has no units because it is a ratio of two masses.

Answer in your head, out loud, or on paper, then tap the card to flip.

What is the difference between relative molecular mass and relative formula mass?

Relative molecular mass refers to the relative mass of simple molecular substances.

Relative formula mass refers to the relative mass of ionic and giant covalent substances.

Answer in your head, out loud, or on paper, then tap the card to flip.

What is the equation that links number of moles, number of particles, and Avogadro's constant?

number of moles =Avogadro’s constantnumber of particles

Answer in your head, out loud, or on paper, then tap the card to flip.

What unit of mass is used to calculate number of moles of a substance using its Mr?


Grams (g)

Answer in your head, out loud, or on paper, then tap the card to flip.

What is Avogadro’s constant?

Avogadro's constant is the number of particles in 1 mole of a substance. The value of the constant is 6.02 x 1023 mol-1.


For example, 1 mole of carbon is exactly 6.02 x 1023 atoms of carbon, and 1 mole of water is exactly 6.022 x 1023 molecules of water.

Answer in your head, out loud, or on paper, then tap the card to flip.

What is a mole?

A mole is a unit of measure that allows us to count extremely large numbers of particles.


1 mole of a substance is the amount of that substance that contains 6.02 x 1023 particles (e.g. atoms, molecules, ions etc.).

Answer in your head, out loud, or on paper, then tap the card to flip.

What does the notation Mr stand for?

Mr stands for either relative molecular mass or relative formula mass.

Answer in your head, out loud, or on paper, then tap the card to flip.

What is the equation that links number of moles (n), mass (m), and Mr?

fg

n =Mr m


n = number of moles (mol)

m = mass (g)

Mr = relative formula mass

Answer in your head, out loud, or on paper, then tap the card to flip.

How do you find the relative formula mass of a compound?

  1. Write down the compound's formula unit.
  2. Identify the number of atoms of each element present in the formula.
  3. For each element, multiply the number of atoms by its relative atomic mass.
  4. Sum up the values obtained in step 3.

Answer in your head, out loud, or on paper, then tap the card to flip.