Chemical Reactions

Question 1

What is a chemical reaction?

Answer 1

A change in which atoms are rearranged to create new substances

Chemical reactions involve the transformation of reactants into products.

Question 2

What do all chemical reactions do?

Answer 2

Make new substances and transfer energy to or from the surroundings

This energy transfer can be in the form of heat, light, or sound.

Question 3

Are most chemical reactions reversible?

Answer 3

No, most chemical reactions are not reversible

It is often difficult to get back to the original substance once a chemical reaction has occurred.

Question 4

What are some signs that a chemical reaction has occurred?

Answer 4

Colour changes, smell, temperature change, fizzing

These signs indicate that new substances have formed.

Question 5

What are some useful applications of chemical reactions?

Answer 5

Making substances such as medicines and fabrics

Chemical reactions are fundamental in the production of everyday materials.

Question 6

What is the difference between chemical reactions and physical changes?

Answer 6

Changes of state and dissolving are reversible reactions, while chemical reactions are not

In physical changes, the original substances can be recovered.

Question 7

Fill in the blank: Changes of state and dissolving are _______ reactions.

Answer 7

reversible

These processes allow the original substances to be obtained again.