Quantitative Chemistry: Calculating Moles of an Element (DONE)

Question 1

Carbon
Ar = 12

12g of carbon = 1 mole of carbon atoms

(1 mole = 602000000000000000000000 of carbon atoms)

Oxygen
Ar = 16

16g of oxygen = 1 mole of oxygen atoms.

(1 mole = 602000000000000000000000 of oxygen atoms)

Answer 1

If we take the relative atomic mass of any element in grams then we’ve got one mole of atoms in that element.

Question 2

What does the mole allow scientists to calculate?

Answer 2

The mole allows scientists to calculate how many atoms of a substance they have in a chemical reaction.

Question 3

If we know the mass of an element that we’re using in a chemical reaction then we can calculate the number of moles using the equation:

Answer 3

Number of moles = Mass (g) / Relative atomic mass Ar

The mass is the mass needed in the chemical reaction and the relative atomic mass is

Question 4

How many moles is in 24g of Mg?

Answer 4

1 ask yourself why?

If we take the relative atomic mass of any element in grams then we’ve got one mole of atoms in that element.

Question 5

You are given a sample of magnesium with a mass of 72g. How many moles of magnesium have you been given?

Answer 5

Number of moles = Mass (g) / Relative atomic mass Ar

3 = 72/24

Question 6

Is the relative atomic mass the number above an element in the periodic table or below?

Answer 6

The relative atomic mass is the number above an element in the periodic table.

Question 7

You are given 160g of calcium. How many moles of calcium have you been given?

Ar calcium = 40

Answer 7

160 / 40 =

4 moles

Question 8

A sample of rock contains 252g of iron. Calculate the number of moles in iron.

Ar iron = 56

Answer 8

252/56 =

4.5 moles

Question 9

You are given a sample of sulphur with a mass of 4064g. Calculate the number of moles in sulphur in the sample.

Ar sulphur = 32

Answer 9

4064/32 =

127 moles