Chemistry Past Questions and Answers

(a)(i) State the two types of hardness in water.<br/>(ii) Name a salt that causes each type of hardness.<br/>(ii) Write a balanced equation for the removal of each type of hardness.<br/>(iv) State one effect of hard water on soap.<br/> <br/>(b)(i) State whether the pH of each of the following is less than, equal to, or greater than 7.<br/>I. Glucose solution II. Chlroine water III. Lime water IV. Sour milk<br/>(ii) Give the difference between the following compounds: I. an acidic oxide and an amphoteric oxide; II. concentrated acid and a dilute acid; Ill. a normal salt and an acid salt<br/> <br/>(c)(i) Iron reacts with H\(_2\)SO\(_4\) according to the equation: Fe\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) ---> FeSO\(_{4(aq)}\) + H\(_{2(g)}\)<br/>Calculate the mass of FeSO\(_4\) that would be produced by 0.5 mole of Fe. [H = 1, S = 32, Fe = 56]<br/>(ii) List two allotropes of sulphur<br/> <br/>(d)(i) State what would La observed when a damp starch-iodide paper is dropped into a gas jar of chloride<br/>(ii) Explain your ansv.er in (d)(i) above.<br/>(iii) State the products formed when ammonia reacts with excess chlorine.

How many orbitals are in the d-sub shell?

An element X has isotopic masses of 6 and 7. if the relative abundance is 1 to 12.5 respectively, what is the relative atomic mass of X?

An atom <sup style='font-size: smaller;'>238</sup><sub style='font-size: smaller;'>92</sub>X decays by alpha particle emission to give an atom Y. The atomic number and mass number of Y are

If 1 mole of sodium contains 6 x 10<sup style='font-size: smaller;'>23</sup> atoms, how many atoms are contained in 0.6 g of sodium? [Na = 23]