Correct Answer: B. labour

Explanation

(a)Opportunity cost is the alternative forgone. The opportunity cost of a product is the alternative which must be given up in order to produce that product. It is the sacrifice made in order to enjoy something else. For example, if a student has N5 to buy either a book or a shirt. If he buys a shirt instead of a book, the opportunity cost is the book which the student has forgone in order to buy the shirt. Money cost, on the other hand, refers to the total amount of money that is spent in order to acquire a set of goods and services. This tallies with the accountant concept of cost. For example, a consumer who spent to buy a shirt has dispensed with cash. The N15 spent is the money cost.

(b) The concept of opportunity cost is relevant to the economies of West African countries. This is because the concept emphasises the basic problem of choice which is the main core of the subject matter of economics as a result of the limited available resources vis-a-vis unlimited wants. Since every economic problem involves choice and every choice involves opportunity cost, therefore, opportunity cost is relevant to the economies of West African countries. The concept involves efficient allocation of scarce resources to pressing needs of the society. It also shows that every activity involves a sacrifice whether on the side of an individual, a firm or a government. The government will decide which sector will take the lion's share of the resources of a country. It helps in government decision-making process.

Correct Answer: A. maize

Explanation

(a)(i) Q belongs to group VI in the periodic table.

(ii) S is strongly metallic in character

(iii) T readily ionizes by gaining one electrons

(iv) P and Q contain two unpaired electrons in the ground state atom;

(v) S readily loses two electrons during chemical bonding

(vi) R does not participate readily in chemical reactions

(vii) S is an s-block element.

(b)

(ii) Atomic radius-increases down a group in the periodic table but decreases from left to right across a period, because as atomic number/ number of electrons increases down a group, number of shells increases, hence atomic size increases. Across a period the number of electrons and protons also increases but there is no increase in the number of shells/ the electrons are added to the same shell. The resultant effect is that the electrons in the orbit experience a greater pull towards the nucleus/ effective nuclear charge increases resulting in decrease in size.

(c)(i) The half-life of a radioactive element is the time taken for half of the total number of atoms in a given sample of the element to decay.

(ii) \(^{210}_{84}PO\) \(\to\) \(^{206}_{82}PO\) + \(^{4}_{2}He\)

(d) The type of chemical bonding that accounts for the following observations:

(i) Chlorine exists as discrete molecules-covalent

(ii) Sodium chlorine dissolves readily in water-ionic/electrovalent

(iii) CuSO\(_{4(aq)}\) forms a deep blue complexion with excess NH\(_3\) –coordinate covalent/dative.

Correct Answer: B) polar

Explanation

One of the reasons why ammonia is very soluble in water is because it is a polar molecule. A polar molecule is one in which the electrons are distributed unevenly, resulting in a partial positive charge on one end of the molecule and a partial negative charge on the other end. Water is also a polar molecule, which means that it has a partial positive charge on one end and a partial negative charge on the other end. This allows ammonia and water to attract each other through hydrogen bonding, which is a type of intermolecular force.

When ammonia dissolves in water, the ammonia molecules break apart and become surrounded by water molecules. The partial positive charge on the hydrogen atoms in ammonia attract the partial negative charge on the oxygen atom in water, and the partial negative charge on the nitrogen atom in ammonia attract the partial positive charge on the hydrogen atoms in water. This results in a homogeneous mixture, with the ammonia molecules evenly distributed throughout the water.

In summary, ammonia is very soluble in water because it is a polar molecule that can form hydrogen bonds with water molecules. As a result, ammonia molecules can dissolve in water and become evenly distributed throughout the solution.

Correct Answer: D. influence of environment and morality in human conduct

Correct Answer: A. generous

Correct Answer: B. speed of sound is less than that of light

Correct Answer: D. Panicum maximum

Correct Answer: B. \(\frac{3}{2}\)