C3 Know It

What does 'conservation' mean?

• A glass room some houses have

• Keeping things the same

• Allowing things to change

• Going from a gas to a liquid

What is the Law of Conservation of Mass in a chemical reaction?

• Matter cannot be created or destroyed, so mass of reactants must equal mass of products

• Matter cannot be created but it can be destroyed, so mass in a reaction can change

• Matter can be created but not destroyed, so mass in a reaction can change

• Matter cannot be created or destroyed, but mass in a reaction can change

What is the reason for a change in mass in a reaction?

• Matter has been destroyed

• New matter has been created

• A gas has been used or made

• A solid has melted away

How many elements are in NaCl?

• 1

• 2

• 3

• 4

How many atoms are in one molecule of NaCl?

• 1

• 2

• 3

• 4

How many atoms are in one molecule of H₂O?

• 1

• 2

• 3

• 4

How many atoms are in one molecule of H₂SO₄?

• 3

• 5

• 6

• 7

What does the atomic number tell us about an atom?

• How many electrons are in the outer shell

• How many protons and neutrons it has

• How many protons it has

• How radioactive it is

What does the atomic mass tell us about an atom?

• How many electrons are in the outer shell

• How many protons and neutrons it has

• How many protons it has

• How radioactive it is

Hydrogen has an atomic mass of 1.

Oxygen has an atomic mass of 16.

What is the relative formula mass of H₂O?

• 3

• 16

• 18

• 32