Top 3 - Quantitative Chemistry

Question 1

What does the conservation of mass mean?

Answer 1

Its means that during a chemical reaction no atoms are destroyed and no atoms are created.

Question 2

How can you determine the number of moles of each substance that would react together from the balanced reaction equation?

Answer 2

The big numbers in front of the reactants and products.

Question 3

State what is meant by the term limiting reactant.

Answer 3

If one reactant gets completely used up then the reaction will stop and this used up one will become a limiting.

Question 4

What volume does one mole of any gas occupy at room temperature and pressure?

Answer 4

24dm(3)

Question 5

Give the equation to calculate concentration.

Answer 5

no. of moles ÷ concentration x volume

Question 6

Give the equation to calculate percentage yield.

Answer 6

percentage yield =
mass of products actually made (g)
—————————————————- x100
maximum theoretical mass of production (g)

Question 7

Give two reasons why it is better to use reactions with high percentage yields.

Answer 7

One it makes your results more accurate

Two you want most if not all the reactants to be used up because if not it is not a fair test.

Question 8

What is Avogadro’s constant

Answer 8

6.022x10x(23)