In what century did the Trans-Saharan trade start?

• A. 8th century
• B. 5th century
• C. 17th century
• D. 4th century

The main achievement of the nationalists in Nigeria was

• A. registration of political parties
• B. economic liberation of the nation
• C. political liberation of the nation
• D. building the nation

An operation * is defined on the set of real numbers by a*b = a + b + 1. If the identity elements is -1, find the inverse of the element 2 under *.

• A. 4
• B. zero
• C. -2
• D. -4

An important aspect of an unwritten constitution is that it

• A. is easy to understand to everybody
• B. safeguards the monarchy
• C. contains customary laws and conventions
• D. is not easily amended

(a) i) Give the name and nature of the radiations that are emitted during radioactivity.

ii) State two differences between chemical reaction and nuclear reaction.

iii) Balance the following nuclear reactions and identify X and Y.

I. \(^{212}_{84} PO\) \(\to\) \(^{208}_{82} Pb\) + X

II \(^{137}_{55}Cs\) \(\to\) \(^{137}_{55}Ba\) + Y

(b) The electron configuration of an element X is: 1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^5\)

(i) Deduce the atomic number of X.

(ii) To what group does X belong?

(iii) Give two properties of the group to which the element X belong.

(iv) Identify element X by name.

(v) Write a balanced equation to represent the reaction between the element X and hot concentrated NaOH.

(c)(i) Explain why: I. graphite is used as a lubricant; II. diamond is used as an industrial cutting tool.

(ii) Write an equation to represent the reaction between aqueous HCI and NH\(_3\) solution.

(iii) Name the type of reaction represented by the equation.

After each of the following sentences, a list of possible interpretations of the sentence is given. Choose the interpretation that you consider most appropriate for each sentence.

They did not know what to expect and so decided to play it by ear. This means that they decided to

• A. listen attentively to everyone
• B. act according to circumstance
• C. pretend to be deaf
• D. prepare for the worst

Final accounts of a company refers to:

• A) Trading and profit and loss account
• B) Profit and loss account and balance sheet
• C) Trading account and balance sheet
• D) Trading , profit and loss account and balance sheet

It takes a shorter time for a liquid to boil at the top of a mountain than at the base because at the top, the

• A. temperature is higher
• B. pressure is lower
• C. humidity is higher
• D. temperature is constant

Given that Y= C+I, where C= 50+0.75 and I = N45m, what is the equilibrium level of income?

• A. N380m
• B. N20m
• C. N180m
• D. N200m

Find the median of this number set: 2, 15, 4, 3, 6, 11, 8, 9, 4, 16, 13

• A. 11
• B. 9
• C. 4
• D. 8