Calculations

Question 1

What is relative formula mass (M) of a compound?

Answer 1

The sum of all the relative atomic masses (A) of the atoms in that compound.

Question 2

Calculate the relative formula mass of magnesium chloride (MgCl₂).

Answer 2

95

Calculation: 24 + (2 × 35.5) = 95.

Question 3

What is the relative atomic mass of magnesium?

Answer 3

24

Question 4

What is the relative atomic mass of chlorine?

Answer 4

35.5

Question 5

Calculate the relative formula mass of calcium hydroxide (Ca(OH)₂).

Answer 5

74

Calculation: 40 + (2 × 16) + (2 × 1) = 74.

Question 6

What does the empirical formula of a compound represent?

Answer 6

The simplest possible whole number ratio of atoms of each element within that compound.

Question 7

How does the empirical formula differ from the molecular formula?

Answer 7

The empirical formula gives the simplest ratio, while the molecular formula shows the actual number of atoms.

Question 8

What is the empirical formula of glucose (C₆H₁₂O₆)?

Answer 8

CH₂O

Simplified by dividing by the largest common factor (6).

Question 9

Find the empirical formula of a compound with the molecular formula C₆H₁₂O₆.

Answer 9

CH₂O

Question 10

What is the relative atomic mass of calcium?

Answer 10

40

Question 11

What is the relative atomic mass of oxygen?

Answer 11

16

Question 12

What is the relative atomic mass of hydrogen?

Answer 12

1

Question 13

True or False: The empirical formula and molecular formula of a compound are always the same.

Answer 13

False

Question 14

Fill in the blank: Relative atomic mass is the average mass of an element, taking into account the different masses of _______.

Answer 14

isotopes

Question 15

What can be found in the periodic table that is relevant for calculating relative atomic masses?

Answer 15

Relative atomic masses of elements.

Question 16

What is the purpose of calculating relative formula mass?

Answer 16

To understand the mass of compounds based on their constituent elements.