Use of amount of substance in relation to masses of pure substances

Question 1

Moles:

Answer 1

• chemical amounts are measured in moles
• symbol = mol
• the mass of one mole of a substance in grams is equal to its relative formula mass
• one mole of one substance contains the same particles, atoms, molecules or ions as one mole of any other substance

Question 2

Mass =

Answer 2

moles x relative atomic mass

Question 3

What is the Avagrado constant?

Answer 3

6.02 x 10 (to the power of 23)

Question 4

What is the Avagrado constant?

Answer 4

The number of atoms, molecules or ions in a mole of a given substance

Question 5

What can be calculated from balanced symbol equations?

Answer 5

masses of reactants and products

Question 6

What is a limiting reactant?

Answer 6

the reactant that is used up/ not in excess (since it limits the amount of products)

Question 7

What happens if a limiting reactant is used?

Answer 7

The amout of the product is restricted to the amount of the excess reactant that reacts with the limiting one

Question 8

Why will one of the 2 reactants be used in excess in a chemical reaction?

Answer 8

to ensure all of the other reactant is used

Question 9

Concentration =

Answer 9

mass/volume

Question 10

What gives a higher or lower concentration?

Answer 10

a smaller volume or larger mass of solute gives a higher concentration
a larger volume or smaller mass of solute gives a lower concentration