01. Introduction to Chemistry

Question 1

What should be observed about substances during practical work?

Answer 1

State (solid, liquid or gas)
Colour/colourless
Crystals/powder (solids
Clear/cloudy (liquids)

Question 2

What changes might be observed during practical work?

Answer 2

Effervescence
Solid appearing/disappearing
Colour change
Sounds
Smells

Question 3

Physical changes

Answer 3

Create no new substances
Easily reversible
Small energy changes
eg Ice melting in a beaker

Question 4

Chemical changes

Answer 4

Create new substances
Difficult to reverse
Large energy changes
eg burning wood

Question 5

Chemical test for water

Answer 5

Anhydrous copper (II) sufate turns white to blue

Question 6

Physical test for water purity

Answer 6

Pure water melts at 0 degrees Celcius
Pure water boils at 100 degrees Celcius

Question 7

Elements

Answer 7

Substance containing only one type of atom

Question 8

Properties of metals

Answer 8

High melting/boiling point
Electrical conductors
Malleable
Shiny

Question 9

Properties of non-metals

Answer 9

Low melting/boiling point
Electrical insulators
Brittle
Dull

Question 10

The diatomic elements

Answer 10

Hydrogen
Nitrogen
Oxygen
Fluorine
Chlorine
Bromine
Iodine
Astatine

Question 11

Compound

Answer 11

Substance containing more than one type of atom, chemically bonded together

Question 12

Heating zinc and sulfur

Answer 12

zinc + sulfur -> zinc sulfide

Question 13

Type of bonding between metals

Answer 13

Metallic

Question 14

Type of bonding between metals and non-metals

Answer 14

Ionic

Question 15

Type of bonding between non-metals

Answer 15

Covalent

Question 16

Type of bonding in sodium chloride

Answer 16

Ionic