Chapter 4

Question 1

What is conservation of mass?

Answer 1

You must have the same number and type of atoms on both sides of the reaction. Mass cannot be lost or created.

Question 2

What are the units for volume?

Answer 2

dm³

Question 3

Why do we need to balance equations?

Answer 3

To maintain the law of conservation of mass

Question 4

How would you convert cm³ to dm³

Answer 4

divide by 1000

Question 5

What must you always use to workout ionic formula?

Answer 5

Crossover rule

Question 6

What is the ionic formula of potassium oxide?

Answer 6

K₂O

Question 7

How would you work out the formula mass?

Answer 7

Add together the atomic mass of the all the atoms present

Question 8

How do you calculate the gradient?

Answer 8

Change In Y / Change In X

Question 9

What is the product of a reaction?

Answer 9

A substance made as a result of a chemical reaction.

Question 10

What is the Avogadro number?

Answer 10

The Avogadro constant is expressed as 6.02 x 10²³

Question 11

What is percentage yield (Chemistry only)

Answer 11

% yeild = (actual mass/theoretical mass) X 100

Question 12

What is atom economy? (Chemistry only)

Answer 12

% Atom economy = (mass of required product / mass of reactant) X 100

Question 13

What is a mole?

Answer 13

One mole of a substance contains 6.02 x 10²³ formula units.

This number is known as the Avogadro constant.

Question 14

How do you work out moles?

Answer 14

Mass (g) / relative formula mass

Mr mole is Fat

Question 15

How do you work out concentration?

Answer 15

Concentration g/dm³ = mass (g) / volume (dm³)

OR

concentration mol/dm³ = mole / volume (dm³)

Question 16

How do you work out moles of gas? (Chemistry only)

Answer 16

number of moles of gas = volume of gas (dm³) / 24