topic 3 - quantitive chemistry: chemical measurements, conservation of mass and the quantitative interpretation of chemical equations

Question 1

What does the law of the conservation of mass state?

Answer 1

No atoms are made or lost during a chemical reaction so therefore the mass of the reactants is equal to the mass of the products.

Question 2

What symbol is used to represent relative formula mass?

Answer 2

Mr

Question 3

What is the relative formula mass (Mr) of a compound?

Answer 3

The sum of all the relative atomic masses of the atoms in the formula.

Question 4

In a balanced chemical equation, what does the sum of all the relative formula mass of the reactants equal?

Answer 4

The sum of the relative formula mass of the products.

Question 5

Why might some reactions appear to observe a change in mass?

Answer 5

Because the reactant or product is a gas and it’s mass has not been taken into account.

Question 6

Whenever a measurement is made, there is always some ___________ about the result obtained.

Answer 6

uncertainty