Chmistry quiz 1 term 3 grade 7

A chemical reaction is

• a change that doesn't make a new substance

• a change that makes a new substance

• a chemical explosion

• reation of chemistry

Atoms are​ (a)   in a chemical reation

• rearranged and join differently
• rearranged and jined in the same way
• Not changed

Chemical reactions are easily reversible

• False

• True

Chemical reactions transfer_______to or from the surroundings

Match the following

• Substances that are made

• Chemical reaction

• Burning magnesium

• Magnesium + oxygen

• Starting substance

• reactant

• Magnesium oxide

• Products

Reactants and products have​ (a)   properties

• different
• The same
• exact

What is this

b

Hazard symbol

fire symblo

Flammable symbol

The number of atoms before and after the chemical reaction is​ (a)  

• the same
• different

The mass of reactants and product stays the same

• True

• False

The mass of the product may be greater than the mass of the reactant if it reacts with oxygen or air

• true

• false