incorrect answers - corrections

Question 1

Describe what happens to the particles in a solid when it is heated to the point of melting

Answer 1

• the particles gain energy
• and therefore vibrate more
• this weakens the forces that hold the solid together and makes the solid expand
• by the point of melting, many of the particles have enough energy to break free of their positions

Question 2

the student keeps adding sodium chloride to the beaker and stirring the solution. Eventually, the sodium chloride starts to settle at the bottom of the beaker. Explain why?

Answer 2

• It is a saturated solution
• the sodium chloride is in excess
• no more can dissolve

Question 3

solubility

Answer 3

Mass of solid obtained/Mass of water removed

Question 4

state the name for a group of atoms held together by covalent bonds

Question 5

give the definition of a relative atomic mass of an element

Answer 5

the relative atomic mass is the average mass of all isotopes in an element, compared to the mass of one atom of carbon-12

Question 6

Suggest why some elements have relative atomic masses that are not whole numbers?

Answer 6

Relative atomic masses are the average results of calculations

Question 7

four carbon allotropes

Answer 7

• graphene
• graphite
• buckminsterfullerene
• diamond

Question 8

In ionic substances, what are free to move?

Answer 8

Ions NOT electrons