Paper 1

Question 1

Explain the variations in melting temperature across the period in terms of the
structure and bonding in these elements.
Na, Mg slightly higher, Al, largest melting temp, Si, P back down (6 marks)

Answer 1

Na, Mg, Al all have metallic bonding, as the density increases, strengthen metallic bonding and thus higher melting temperature

Si giant covalent lattice- a lot of energy required to break the covalent bonds

P simple molecular- only weak London forces, lower temperatures

Question 2

what is the system equal to in graph

Answer 2

gradient

Question 3

Explain why the melting temperature of sodium benzoate is higher than the
melting temperature of potassium benzoate

Answer 3

sodium has a smaller ionic radius even though they have the same charge
strength of ionic bond increases

Question 4

Using H^2/ACID

Answer 4

You have a weak acid.

You know the concentration of the acid.

You know the Ka of the acid.

You want to find the [H⁺] (and then the pH).