Correct Answer: A. 800kgm³

Explanation

R.d = \(\frac{0.4}{0.5}\) = 0.8

0.8 = \(\frac{\text {Density of oil}}{\text{Density of water}}\)

0.8 = \(\frac{\text {Density of oil}}{1000}\)

Density of oil = 800kgm³

Correct Answer: D. reach

Correct Answer: B. troposphere

Correct Answer: B. Overdraft

Explanation

A security is a financial instrument, typically and financial asset that can be traded e.g bonds, debenture, stock, shares etc.

Correct Answer: C. 4/3

Correct Answer: D. systematic growth of the body

Correct Answer: B) Ribosome

Explanation

Proteins are important molecules that perform various functions in the body. The question is asking where protein synthesis takes place. Protein synthesis is the process of making new proteins. The correct answer is option B, ribosome. Ribosomes are small structures in the cell where protein synthesis occurs. They are found in both prokaryotic and eukaryotic cells. During protein synthesis, the ribosome reads the genetic code in messenger RNA (mRNA) and uses it to assemble amino acids into a polypeptide chain. The polypeptide chain then folds into a functional protein. Ribosomes can be found free in the cytoplasm or attached to the endoplasmic reticulum (ER). The ER is a network of membranes in the cell that is involved in protein processing and transport. The other options in the question, Golgi body, mitochondria, and nucleus, are all organelles in the cell, but they are not directly involved in protein synthesis. The Golgi body is involved in processing and packaging proteins for transport. Mitochondria are organelles that produce energy in the form of ATP. The nucleus contains genetic material (DNA) and is involved in gene expression, but protein synthesis occurs outside the nucleus. In summary, protein synthesis takes place in the ribosome, which is a small structure in the cell. The ribosome reads the genetic code in mRNA and uses it to assemble amino acids into a polypeptide chain, which then folds into a functional protein.

Correct Answer: B. rung

Correct Answer: B. Blood

Explanation

(a) (i) The cations and anions attract the polar water molecules the energy released as the ion-dipole forces are formedprovides the energy to break the electrostatic forces of attraction between the oppositely charged ions in the potassium chloride.

OR

The water molecules split KCl into free ions with a release of energy known as lattice energy. The free ions are hydrated/surrounded by water molecules. This is known as the hydration energy.

(ii) More energy is needed to overcome the ion-ion attraction hence the

dissolution process is endothermic /

OR

lattice energy is greater than hydration energy.

(b) (i) Magnesium is more reactive than iron therefore magnesium reacts

preferentially / acts as a sacrificial anode.

(ii) Iron oxidizes to Fe\(^{2+}\) by oxygen and water to give Iron (II) hydroxide / Fe\(^{2+}\) and

OH\(^-\) formed. Further oxidation gives hydrated Iron (III) oxide / Fe2O\(_3\).xH\(_2\)O

(iii) Presence of (dissolved) oxygen / air

(c) (i) It is a reaction that occurs without being driven by some outside / external force.

(ii)

- G must be negative

- the products are more random, more disorganized than the reactants /

entropy of products is greater than entropy of reactants / entropy must increase

(iii) Sodium is in Group I and is more reactive metal than calcium that is in

Group II. / sodium is more electropositive than calcium / higher in the reactivity series

(iv)

(d) Mr (PbCO\(_3\)) = 207 + 12 + 16(3)

= 267g mol\(^{-1}\)

(e)

(i) van der Waal’s forces

(ii) hydrogen bonding