Chemical Reactions

Complete the sentence: In a chemical reaction...

• No new substance is made

• A new substance is formed

Organize these examples into the right categories

Groups:

(a) Chemical reaction

,

(b) Physical change

• Digesting food

• Breaking a pencil

• Baking a cake

• Melting chocolate

• Boiling water

• Fireworks

Select all the observations which can be a sign of a chemical reaction

• Effervescence

• A temperature change

• Moulding into a new shape

• A colour change

A solid that forms when two solutions are mixed and react is called a ​ (a)  

• precipitate
• effervess
• exotherm

What sign of a chemical reaction can be observed in this reaction?

• Effervescence

• A precipitate forming

• Melting

In an ​ (a)   reaction, energy is given out to the surroundings.

• exothermic
• endothermic

Organise these examples into the right categories

Groups:

(a) Exothermic

,

(b) Endothermic

• Burning petrol

• Hand warmer

• Ice pack