C3

Question 1

How do you work out the number of moles?

Answer 1

Mass in grams (of an element or compound) DIVIDED BY the molar mass (of an element or compound).
Use triangle

                 Mass  \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ No. Of moles   X   Molar mass

Question 2

How do you work out the concentration of a substance?

Answer 2

Concentration (g/dm^3) = mass of solute (g) DIVIDED BY the volume of solvent (dm^3)

            Mass  \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Concentration   X  volume

Question 3

How do you calculate the mass of a product formed in a reaction?

Answer 3

1) write out the balance equation
2) work out the relative formula mass (Mr) or the reactant or product.
3) work out how many moles there are in the substance you know the mass of.
4) use the balanced equation to work out how many moles there’ll be of the other substance.
5) use the number of moles to calculate the mass.

Question 4

what is the Avogadro value?

Answer 4

6.02 x 10^23