3.1.2.1 Relative Atomic Mass and Relative Molecular Mass

Question 1

What type of zeroes are significant?

Answer 1

• captive zeroes e.g. 2056.73
• trailing zeroes e.g. 46.50
• trailing zeroes e.g. 25,000 (depends)

Question 2

What type of zeroes are not significant?

Answer 2

leading zeroes e.g. 0.025

Question 3

In addition o&subtraction to how many decimal points do you provide the answer?

Answer 3

in performing addition or subtraction you report your answer to the same number of decimal places as the number with the least number of decimal places in the question

Question 4

In division and multiplication to how many significant figures do you provide your answer to?

Answer 4

in performing multiplication or division you report your answer to the same number of significant figures as the number with the least number of significant figures in the question

Question 5

What will the term relative formula mass be used for?

Answer 5

ionic compounds

Question 6

Relative atomic mass (Ar):

Answer 6

average mass of an atom of an element compared to 1/12th the mass of an atom of 12C, which is taken as exactly 12

Question 7

Relative isotopic mass:

Answer 7

mass of an atom of an isotope of the element compared with 1/12th the mass of an atom of 12C which is taken as exactly 12

Question 8

Relative molecular mass (Mr):

Answer 8

the average mass of a molecule compared to one twelfth of the mass of one atom of carbon-12 which is taken as exactly 12