Advanced level 2025 South West mock Chemistry 2
Advanced level 2025 South West mock Chemistry 2
1.) a) (i) Define
A) Relative Atomic Mass
i» *
B) Limiting Reagent
ii) C alculatc the nuinbei ol potassium ions present in 3.0 g of a solution of KcCOj.
(5 marks)
b) i) What is a Bom- Haber cycle?
^ (i) W hat is the coordination number of a hexagonal close packed crystal?
ii) Which instrument is used to determine crystal structures?
(2 marks)
d) (i) State tlie equilibrium law
ii) For the reaction PCls(g) ^ PCb(g) + Ck(g); AH = +93 kJ mol
A) ^ rile an expression ior the equilibrium constant, Kc.
B) W hat w ill be the ettect on the equilibrium constant value when the temperature of the reaction is
increased?
(3 marks)
e) Calculate the pH of a 0.03 M solution ofNaOH
2.) a) i) What is a nuclear reaction?
ii) Write an equation for the beta decay of 234 90Th to the isotope protactinium (Pa)
(2 marks)
b) i) The mass spectrum of a vaporized sample of potassium, atomic number 19 shows peaks at 39,
40 and 41, with relative abundances of 93.22, 0.12 and 6.77 respectively.
Calculate the relative atomic mass of potassium
1
i ii) Give two reasons why particles must be ionized before analyzing in a mass spectrometer
!
(4 marks)
c) i) Differentiate between metallic bonding and covalent bonding
ii) Give the shape and the bond angle for each of the compounds NH3 and Bib.
A: NH3
Shape;
Bond angle;
B: BH3
Shape;
Bond angle;
iii) Explain why BF3 reacts with NH3
(5 marks)
d) i) Define
A: Rate Constant
