Questions?

Question 1

Write a definition for Element, compound and molecule.

i) Element -
ii) Compound -
iii) Molecule -

Answer 1

i) Element - a substance that is made up of only one type of atom - pure
ii) Compound - a substance that is made up of 2 or more types of atoms - not pure
iii) Molecule - a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.

Question 2

Recall the maximum number of electrons that can be held in:
i) The first shell -
ii) The second shell -
Explain what a valence shell is:

Answer 2

i) The first shell - 2
ii) The second shell - 8
Explain what a valence shell is: the outermost shell - outside shell

Question 3

Josie has a packet of ammonium nitrate and water. She breaks the package to allow the substances to mix and react. She notices that as they do so, the packet feels cool.

• Identify the type of reaction that has occurred:
• Contrast exothermic and endothermic reactions

Answer 3

a) Identify the type of reaction that has occurred:
- Endothermic reaction
b) Contrast exothermic and endothermic reactions
- Endothermic reaction decreases in heat and becomes cool to touch
- Exothermic reaction attracts heat and produces heat making it environment hot-