3.2 Masses Of Atoms And Moles

Question 1

What is the shorthand for relative formula mass?

Answer 1

Mr

Question 2

What is a mole?

Answer 2

The relative atomic mass of an element in grams (usually shown in periodic tables)

Question 3

What atom do we use as a standard atom to compare the masses of all other atoms?

Answer 3

Carbon 12

Question 4

What is the shorthand for relative atomic mass?

Answer 4

Ar

Question 5

What does the Ar of an element depend on?

Answer 5

The isotopes the element contains, the Ar is an average of the isotopes however it usually ends up, when rounded, as the mass number of the main isotopes

Question 6

Why is the Ar of chlorine not a whole number?

Answer 6

It has 2 main isotopes and the Ar is an average value

Question 7

How do you find the relative formula mass?

Answer 7

Add together the Ar’s of all the atoms in its formula

Question 8

When is using moles useful?

Answer 8

When we need to work out how much of a substance reacts or how much product we will get