introduction

Question 1

how to describe a substance

Answer 1

• solid, liquid or gas?
• coloured or colourless?
• crystalline or powdered?
• clear or cloudy?

Question 2

how to describe changes

Answer 2

• fizzing?
• solid appeared or disappeared?
• change of colour?
• unusual sounds or smells?

Question 3

what is a physical change

Answer 3

no new substance created, easy to reverse, absorb or release small amounts of energy

Question 4

what is a chemical change

Answer 4

create new substance, difficult to reverse, absorb or release LARGE amounts of energy

Question 5

chemical test for water?

Answer 5

anhydrous copper(ll) sulphate: turns from white to blue

Question 6

physical test for water?

Answer 6

• melting point = 0 degrees
• boiling point = 100 degrees
  (pure water matches these properties closer)

Question 7

what are the 8 diatomic elements

Answer 7

H2, N2, O2, F2, Cl2, Br2, I2, At2

Question 8

definition of a compound

Answer 8

a substance containing more than one type of atom, chemically bonded together

Question 9

how can you make a compound

Answer 9

heating their elements together

Question 10

how to illustrate diffusion of gases

Answer 10

ammonium chloride in a tube

Question 11

how does ammonium chloride in a tube work

Answer 11

2 gases, ammonia and hydrogen chloride, diffuses from the end of the sealed tube
when they meet they form a compound of ammonium chloride which forms a white smoke

Question 12

what happens if you heat up the tube

Answer 12

white smoke forms faster because the particles move faster