Advanced level 2023 south west regional mock chemistry 2

Advanced level 2023 south west regional mock chemistry 2

Advanced level 2023 south west regional mock chemistry 2

Define Avogadro constant

(ii) Calculate the number of chlorine atoms present
(Avogadro constant, L— 6.02 * 10 ) (2 murks)
b) (i) What do you understand by the term;
A: Empirical Formula: aT
B: Molecular Formula:
(ii) Analysis shows that 2.215 g of the chloride of an element (E) contains 1.065 g of chlorine.
Determine the formula of the chloride given that the relative atomic mass of E is 115.

(4 marks)
c) In the experiments for the discovery of subatomic particles, some observations were made. State the
significance of each of the following observations:
(i) Cathode rays were able to cast a sharp shadow of an object placed in its path.
£
a
(ii) The electric counter was able to deflect only when a block of paraffin wax was placed between the
beryllium foil and the counter.
(2 marks)
d) The mass spectrometer is an instrument used to determine the relative atomic mass of an element.
?i (i) Why must the interior of the instrument be cvacuated before being used? a
I a a
(it) Chlorine consists of two isotopes in nature namely Chlorine-35 and Chlorine-37. If the relative
atomic mass of Chlorine is 35.5, determine the relative abundance of each isotope.