Question 1

1. transition metals

2. boiling point

3. x → y = the particles are gaining energy and overcoming the intermolecular forces and turning into gas from a liquid

   y → x = the gas particles are slowly losing energy and turning back into liquid from a gas

4. b

5. 56+32+(4x16) = 152

Question 2

1. covalent

2. The cork flies out because the pressure difference inside the bottle has been released. The champagne flies out due to increase in pressure. Bubbles can be seen due to the CO2 being released.

3. MrCO2 = 12+(2x16)

   = 44

   n = 440,000/44

   = 10,000 mol

   1:1 ratio

   MrCH3OH = 12+4+16

   = 32

   m = 32 x 10,000

   = 320,000

   = 3.2 x 10^5 g

4. A catalyst is a substance used in a chemical reaction that does not undergo chemical change itself. It provides the reaction an alternative pathway and reduces the activation energy and increases the rate of reaction

Question 3

1. oxygen
2. 4, 3
3. Argon has a complete outer shell as it has 8 valance electrons. This means that it is a stable atom and does not form compounds as it doesn't need to accept more electrons.
4. Air consists of many gases, like oxygen. Unlike argon, it is reactive as it does not have a complete outer shell and is an unstable atom. Therefore, when in contact with the metal filament, they will combust causing an explosion.

Question 4

1. What is the effect of F- ions on tooth filling materials?

2. IV: filling material

   DV: concentration of F- ions

   CV: initial concentration, mass of filling material

3. The second students method is invalid. This is because the filling material is not fully covered in the fluoride ion solution.