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- Magnessium has a stronger metallic bond than calcium because it has smaller atomic radius. - Atomic radius decreases across a period and increases down a group.

No expanded working has been attached for this question yet. The verified answer is Option C.

- Phosphorus also has 15 electrons. - Here we have P3- which means that this atom has gained 3 electrons. So, P3- has 18 electrons.

- The mass number of an atom is its total number of protons and neutrons

- An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration. - Hybrid orbitals are useful in the explanation of molecular geometry and atomic bonding properties and are symmetrically disposed in space.

Mass concentration is the only quantity that is not a molar quantity; it's a measure of mass per unit volume. Mass Concentration:This refers to the mass of a substance (solute) present in a given volume of solution (or mixture), often expressed in units like grams per liter (g/L) or milligrams per liter (mg/L).

- Dilution Factor is the factor by which the stock solution is diluted. It may be expressed as the ratio of the volume of the final diluted solution (V2) to the initial volume removed from the stock solution (V1) - The dilution factor is the total number of unit volumes in which your material will be dissolved.

- CaCl2 is an ionic compound owing to the large electronegative difference between the calcium atom and chlorine atom, which is greater than 2.0. In calcium chloride, the calcium atom donates its two electrons and become cation whereas each chlorine atom gain one electron, donated by Calcium, and get a negative charge. - Ionization energies are always positive numbers, because energy must be supplied (an endothermic energy change) to separate electrons from atoms. - Chlorine has a high ionization energy - Chlorine has high electron affinity among the elements. Its high affinity can be attributed to its large atomic radius, or size. Because chlorine's outermost orbital is 3p, its electrons have a large amount of space to share with an incoming electron.

examples of biodegradable Food waste. Paper waste. Human waste. manure. sewage. Sewage sludge - Glass, metals, electronic devices, computer parts, batteries, medical waste, plastic bags, plastic bottles, tetra packs, and carbon paper are a few examples of non- biodegradable materials.

(a) (i) Faraday's first law of electrolysis states that the amount of a substance discharged at/dissolved from an electrode is directly proportional to the quantity of electricity that passes through the electrolyte. OR - The mass of an element deposited at the electrode is directly proportional to the quantity of electricity passed. (ii) Strong electrolytes dissociate/ionize completely in aqueous solutions while weak electrolytes dissociate/ionize only slightly/partially in aqueous solution. (b) -it burns in air/oxygen; - it undergoes addition reaction;-it undergoes polymerization, - it undergoes substitution/precipitation reaction. (c)i) hydrocarbon with double/triple bond/multiple bonds between at least a pair of carbon atoms. (ii) CH\(_3\)COOH + CH\(_3\)OH ⇌ CH\(_3\)COOCH\(_3\) + H\(_2\) (ii) Methylethanoate (d) addition of concentrated H\(_2\)SO\(_4\) ; - removal of the ester as soon as it forms; - increase the concentration of one of the reactants. (e) 65.0g of Zn\(^2+\) will produce 6.02 x 10\(^23\) molecules of H\(_2\), OR 65.0g Zn = I molecule of H\(_2\) ∴ 3.75g of Zn = \(frac{3.75}{ 65}\) X 6.02 x 10\(^23\) = 3.4 X 10 molecules (f) Sea level rising: -severe climate changes,depletion of coral reefs; -alters ecosystem balance/setting animal on the move; - severe drought; flooding or( areas); - polar ice melting (g)(i) equation B, H\(_2\) +C\(_2\)H\(_4\) --> C\(_2\)H\(_6\) (ii) In equation B, H changes from zero to-1; C changes from +2 to +3 as Concentration (i) (h)(i) an electron in an atom exists/revolves a circular orbit; - energy of an electron is quantified / has a fixed value; - an electron emits energy in the form of radiation when it moves from a higher energy state to a lower energy State. (ii) Bohr's model cannot explain the more complicated spectra lines observed in spectra Other than that of hydrogen. (i) temperature; pressure/volume; -concentration (j) (i) produces a gas/effervescence/bubbles- given off;- HCI will produce a more vigorous reaction/CH\(_3\)COOH will produce a less vigorous reacton.

a)(i) They are geometric/cis-trans isomers; (ii) Compound A: Trans 1, 2- dichloroethene, Compound B: Cis - 1,2- dichloroethene. (iii) The chemical properties will be the same (iv) because they both contain the same functional group; - they have same type of atoms connected in the same way b)(1)- boiling takes place at a specific temperature; - boiling takes place throughout the liquid, - bubbles are formed vapour pressure is equal to atmospheric pressure (ii) I. It increases the boiling point of the water, ii. It lowers the boiling point of the water. BOILING EVAPORATION Occurs throughout the liquid Occurs only at the surface of the liquid Occurs at a particular constant temperature Takes place at all temperatures Has no cooling effect Has a cooling effect Exothermic Endothermic Occurs using external source of heat/not spontaneous Occurs using internal energy/spontaneous Bubbles are observed Bubbles are not observed Not affected by humidity Affected by humidity Fast process Slow process Unsaturated solution Saturated solution Can dissolve more solute at that temperature Cannot dissolve any more solute at that temperature Does not contain undissolved solute at that temperature Contains undissolved solute at that temperature C. (ii) -increasing the temperature; - increasing the volume of solvent (iii.) - temperature; - volume of solvent; - nature of solute; - nature of solvent D. (i) The amount of substance containing 6.02 x 10\(^23\) particles of that Substance/amount of substance containing as many particles as there are atoms in 12g of carbon 12. (ii) n (HCI) = 25.0 x 10 dm3 x 0.1 moldm3, n (HCI) 2.5 x 10\(^-3\) mol. From the equation of the reaction: Mole of HCI = 0.025 x 0.1 = 0.0025 -->mol of MgO = 0.0025 / 2 = 0.00125mol Molar mass of MgO = 24+ 16 =40 mass of MgO= 0.00125x 40 = 0.05g (e) - are malleable, -are ductile; - are lustrous; - have high melting point/boiling; - have high tensile strength/hard Strong -high density; -solids at room temperature except mercury; - good conductors of heat; -good conductors of electricity: sonorous

(a) (i) Conc HCL and MnO\(_2\) KMnO\(_2\) (II) Conc H\(_2\)SO\(_4\) (III) Downward delivery / upward displacement of air. (ii) 16HCL + 2KMnO\(_4\) --> 2MnCl\(_2\) + 2KCl + 8H\(_2\)O5Cl\(_2\) OR MnO\(_2\) + 41HCI --> MnCl\(_2\) 2H2O\(_2\) + CI\(_2\) (III) 3Cl\(_2\) + 6NaOH --> 5NaCl + NaClO\(_3\) + 3HO\(_2\) (b) (i) - Hematite: - Coke: - Limestone (ii) C + CO\(_2\) --> C + CO\(_2\) --> 2CO Fe\(_2\)O\(_3\) ⇒ Fe + 3CO\(_2\) . CaCO\(_3\) --> CaO + CO\(_2\) CaO + SiO\(_2\) --> CaSiO\(_3\) (iii) Pig Iron (iv) because it contains impurities not pure. ( c) (i) the dissolution of ŠO\(_3\) in water is highly exothermic, mist of acid droplets would be formed. (ii) it is produced on a large scale: - it is required by many industries as a raw material ; it is in high demand by other industries. (iii) I. Acting as a displacement/precipitating agents; ii. Acting as an Oxidizing agent (d) 2CH\(_3\)CH\(_2\)CH\(_2\)OH + 2Na --> 2CH\(_3\)CH\(_2\)CH\(_2\)ONa + H\(_2\); OR 2CH\(_3\) H\(_7\)OH + 2Na --> 2CH\(_2\)H\(_7\)ONa + H\(_2\)

(a)(i) (ii) I.Activation = 210 - 100 = 100kj II. \DeltaH = H\(_p\) - H\(_p\) = 54 - 100 = -46kj (iii) Q\(_2\) + R\(_2\) ⇌ 2QR (iv) The reaction is exothermic (v) Because energy is given out \DeltaH is negative energy of product is lower than energy of reactant. . IS\(_2\) 2S\(_2\)P\(_3\) 1S\(_2\) 2S\(_2\) 2P\(_5\) 1S\(_2\) 2S\(_2\) 2P\(_6\) 3S\(_2\) 1S\(_2\) 2S\(_2\) 2P\(_6\) 3S\(_2\) 3P I I. Elements H and G lI. Element H III. Element F IV. GF\(_2\). (c) Isotopy is simply a phenomenon whereby elements exist in various forms that have the exact same chemical properties but different atomic mass. (d) Atoms - Ions - Molecules

(a)(i) ammonia: - hydrogen chloride: - sulphur (iv) Oxide (ii) To demonstrate high/extreme solubility of gases HCl / NH\(_3\) / SO\(_2\) in water. (iii) A flask. fitted with a glass jet is filled with dry ammonia or any soluble gas. Inject water through the inlet into the flask. this dissolves the ammonia soluble gas and causes a fountain through the jet. OR -a round bottomed flask is filled with gas and fitted with two delivery tubes and closed by use of clips A and B; - Invert the flask into a beaker of water: - open a clip A to allow small volume of water to enter the flask. then close it - the gas dissolves in water causing sudden reduction of pressure in the flask: open clip B: reduced gas pressure causes water from the beaker through delivery tube into the flask forming fountain. (b) (i)-Textiles: Tannery: - Brewery Bottling company: Soaps and detergents: - food industry: pharmaceuticals: - cosmetics: petrochemical Industry: - petroleum industry; dyes: paints; agrochemicals: fertilizers; - pesticides; plastic (ii) Improvement in the standard of living of people: - employment opportunities: - development in the community: pollution (air. land. water. etc.) (c) (i) - coke; - coal tar; - coal gas: ammoniacal liquor (ii) Coke (solid) fuel production of water gas extraction of metals. Coal tar; synthesis of chemicals.perfumes dyes/paints / drugs / plastics explosives / tanning of roads. Coal gas; as fuel (in homes and industries). Ammoniacal liquor;- production of fertilizer (d)i) calcium hydrogen trioxocarbonate (IV): -calcium tetraoxosulphate (Vi): - magnesium tetraoxosulphate (Vi) - magnesium hydrogen trioxocarbonate (IV); - iron (III) chloride. (ii)heating the water to boiling / distillation: addition of calculated amount of calcium hydroxide: - addition of washing soda crystals: - ion exchange resin permutit (iii)- calcium ions in the water are good for method children's teeth and bones: it helps to reduce heart diseases; does not dissolve lead pipes: - tastes better than soft water:- provides calcium salts used in manufacturing of food in plants: production of exoskeleton of animals / shells Tannery:

(a) Burette reading/Titration 1st Titration 2nd Titration 3rd Titration Final burette reading (cm\(^3\)) 16.50 16.10 21.10 Initial burette reading (cm\(^3\)) 0.00 0.00 5.00 Average volume of acid used 16.50 16.10 16.10 The first titration as a trial Average volume of acid used = \(\frac{16.10 + 16.10cm^3}{2}\) = \(\frac{32.20cm^3}{2}\) = 16.10cm\(^3\) (b)(i) Concentration of A in mol/dm\(^3\) 500cm\(^3\) of solution contains 5.00g of HNO\(_3\) 100cm\(^3\) of solution will contain \(\frac{5.00}{500} \times \frac{100}{1}\) = 10.00 gdm\(^{-3}\) Molar mass of HNO\(_3\) = (1 x 1) + (14 x 1) + (16 x 3) = 1 + 14 + 48 = 63gmol\(^{-1}\) Using the relation: Concentration g/dm\(^3\) = molar conc.moldm\(^{-3}\) x molar mass 10.00 = molar conc. moldm\(^{-3}\) x 63 Concentration of A = \(\frac{10.00}{63}\) = 0.15873015873 moldm\(^{-3}\) = 0.158 moldm\(^{-3}\) (ii) Concentration of B in moldm\(^{-3}\) Using the formula \(\frac{C_AV_A}{C_BV_B} = \frac{N_A}{N_B}\) \(\frac{0.159 \times 16.10}{C_B \times 25.0} = \frac{1}{1}\) \(C_B = \frac{0.159 \times 16.10 \times 1}{25.0 \times 1}\) = 0.0102396 moldm\(^{-3}\) \(C_B\) = 0.102 moldm\(^{-3}\) (iii) Concentration of B in gdm\(^{-3}\) concentration g/dm\(^{-3}\) = molar concentration of moldm\(^{-3}\) x molar mass Molar mass NaOH = 40g/mol Concentration of B = 0.102 x 40 = 4.08g/dm\(^3\) (iv) Mass of NaOH No. of moles of NaOH = \(\frac{\text{molar conc.moldm}^{-3} \times volume}{1000}\) = \(\frac{0.102 \times 250}{1000}\) = 0.0255 mole from the equation 1 mole of NaOH = 0.055mole of NaNO\(_3\) 0.0255 mole of NaOH = 0.0255 mole of NaNO\(_3\) molar mass of NaNO\(_3\) = 85 gmol\(^{-1}\) mass of NaNO\(_3\) = 0.0255 x 85 = 2.1675g