Chemical and Physical Change

Question 1

Physical Change

Answer 1

The substance involved in the change is structurally the same before and after the change ie. the chemical nature of the substance does not change. A physical change rearranges molecules/particles but doesn’t affect their internal structures.

Question 2

Types of Physical Changes

Answer 2

• Texture
• Shape
• Temperature
• Change in state of matter

Question 3

Changes of State

Answer 3

• Solid → Liquid = Melting
• Liquid → Gas = Evaporating
• Gas → Liquid = Condensing
• Liquid → Solid = Freezing
• Solid → Gas = Subliming
• Gas → Solid = Deposition

Question 4

Physical States

Answer 4

Solids → molecules are arranged in regular, repeating patterns. Are held firmly in place but can vibrate
Liquids → molecules flow easily around one another, kept from flying apart due to attractive forces, vibrate
Gases → molecules fly all directions at speed, far apart so attractive forces are insignificant, vibrate

Question 5

Ability to Compress or Change Volume

Answer 5

• Only gases can be compressed to a fixed shape
• Solids and liquids cannot be compressed
• Liquids fill the shape of their container

Question 6

Temperature

Answer 6

• Is linked to the kinetic energy of atom-scale particles
• The greater the average kinetic energy of the particles, the higher the temperature

Question 7

Solids, Liquids and Gases

Answer 7

• As a substance passes from a gas, to a liquid and ultimately a solid state, its particles have reduced their degree of motion
• The addition of heat increases the kinetic energy of the particles so substances may change their states from solids to liquids to gases

Question 8

Non-Newtonian Fluids

Answer 8

• Are fluids with properties different in any way to typical fluids
• Most commonly, the viscosity differs from regular fluids

Question 8

Signs of Chemical Changes

Answer 8

• Permanent changes in colour
• Changes in temperature
• Changes in odour
• The production of light
• The formation of gases
• A new precipitate appearing

Question 9

Chemical Change

Answer 9

• Occurs when the substance’s chemical composition changes during a chemical reaction and forms a new chemical substance
• Chemical bonds are broken and new ones are formed

Question 10

Reactants

Answer 10

• Substances that react together and start a chemical reaction

Question 10

Products

Answer 10

• Substances formed in a chemical reaction and are produced

Question 11

Metals

Answer 11

• Metallic lustre
• Good conductors of heat and electricity
• Malleable

Question 12

Diffusion

Answer 12

• Random movement of particles from an area of high concentration to low concentration

Question 12

Non Metals

Answer 12

• No metallic lustre
• Poor conductors of heat and electricity
• Brittle

Question 12

Lattices

Answer 12

• When metals and non metals react, they form lattices of metallic salts or ionic compounds
• When metals and non metals react, they produce metal compounds (typically a salt)
• All metals and all metal compounds are lattices