3.3 Mole Calculations

Question 1

What is a mole?

Answer 1

• 1 Mole is the number of particles obtained by weighing out the Ar or Mr in grams.
• It is equal to 6.02 x 10^23 (Avogadro’s constant)

Question 2

One mole of a substance =

Answer 2

6.02 x 10^23 (Avogadro’s constant) particles of that substance.

Question 3

What is the molar mass of a substance?

Answer 3

The molar mass is the weight of 1 mole of particles.

Question 4

What is the formula triangle for mass, number of moles, and mass of one mole?

Answer 4

Mass (g)
Mass of 1 mole x Number of moles.

Question 5

Calculating masses from equasions:

Answer 5

• Note balanced equasion.
• Write down Ar or Mr for each substance.
• Use relative mass to change moles to grams.
• This gives theoretical mass (the ratio of masses)

Question 6

Avrogadro’s Law:

Answer 6

1 mole of every gas at rtp has the same volume. (24dm^3)

Question 7

Calculation triangle for gas volumes:

Answer 7

Volume at rtp (dm^3)
No of moles x 24 dm^3

Question 8

The concentration of a solution is:

Answer 8

The amount of solute that is dissolved in 1 dm^3 of solution.

Question 9

Calculation triangle for concentration of solutions:

Answer 9

amount of solute (mol)
concentration (mol/dm^3) x volume (dm^3)