Question Library

The most formal way to adjust presidential powers in law is through an act of the National Assembly.

Weight of handbag(W) = 162N acting vertically downward Angle of pull (\(\theta\)) = 60º to the vertical Since the handbag is in equilibrium, the total vertical force must equal the weight of the handbag. Let F be the force exerted by each student on the handle. The vertical component of the force from each student is given by: Fv = F cos 60º but there are two students 2Fcos60º = 162 2F(0.5) = 162 ( cos60º = 0.5) F = 162 ( since 2 x 0.5 = 1) Therefore, the force exerted by each student on the handbag is: 162N ​

A mixture of iodine and sulphur can be separated by adding Carbon disulphide that is (CS₂) then stir the solution and filter it . As sulphur dissolved in CS₂, so it come into filter and got separated from the mixture.

Sieving is a technique used to separate solid particles of different sizes in a mixture. The separation is based on the relative sizes of the particles and the holes in the sieve. Answer: Option C

The chemical formula for aluminum silicate is Al₂SiO₅. It's also sometimes written as Al₂O₃·SiO₂ because silicates are often complex. Aluminum silicate is a mixture of aluminum, silica, and oxygen. It can be a mineral or combined with water to form a clay.

2CO + O2 → 2CO2 50cm3 → 25cm3 20% * 150 = 30cm3 30 cm3 is the volume of oxygen available for the reactions. But only 25 cm3 is required; therefore O2 is in excess

\(K_2\)C\(r_2\)\(O_7\) + HCl → C\(l_2\) + KCl + CrC\(l_3\) + \(H_2\)O Balancing the equation, we have \(K_2\)C\(r_2\)\(O_7\) + 14HCl → 3C\(l_2\) + 2KCl + 2CrC\(l_3\) + 7\(H_2\)O

From P1V1 = P2V2 1 * V1 = 1.5 * V2 ((1 * 300)/1.5) = V2 ∴ V2 = 200 cm3

Mole fraction = \(\frac{\text{Partial pressure of component}}{\text{Total pressure of compound}}\) = \(\frac{452}{780}\) = 0.579

The fundamental difference between the three states of matter is their degree of movement, gaseous particles are very loosely packed hence they can move about easily. The particles of solids are closely packed so solids only make vibrational movement, while liquid particles can move past each other because their particles are not as closely packed as those of solids.

The valence electron of the elements in the same period increase progressively across the period due to an increase in atomic number

\(_{22}X^{2+}\) has 22 electrons but has been ionized to 2+ by giving off 2 electrons. Hence, the ion \(_{22}X^{2+}\) has 20 electrons. The electronic configuration = 1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^6\) 3d\(^2\) the general trend for the first-row transition metals is that they lose electrons from their 4s orbitals first before 3d when forming ions. but this is not true for chromium and copper due to stability related to half-filled or completely-filled 3d orbitals

Apart from the fact that there are delocalised ions around the metals, the metallic atoms remain the same, hence no new substance is formed. However, covalent, co-ordinate and electrovalent bonding involves formation of new substances. Option A is the answer

The half-life of a species is the time it takes for the concentration of that substance to fall to half of its initial value. Since every elements have their specific half life which is neither affected by temperature nor pressure, the knowledge of half life can be used to detect the particular element.

CO2 is linear because the electron pairs around the central carbon atom repel each other, forcing the two oxygen atoms to push as far as possible to either side of the carbon atom, hence its bond angle is at 180 deg; H2O is bent because of the repulsion between the oxygen atom's unshared electrons and the shared electrons between the oxygen and hydrogen atoms, and CH4 has a tetrahedral shape because of the repulsion between the four pairs of bonding electrons around the central carbon atom.