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(a) Gases that are soluble in water are: - Ammonia - Hydrogen chloride - oxygen, - carbon dioxide, - Sulphur dioxide, - chlorine, and - hydrogen sulfide. (b) Apparatus that could be used to measure volume of solutions accurately: - volumetric flask, - graduated cylinder, - burette, or - volumetric pipette. (c) In a laboratory, fume cupboards are essential safety equipment used to capture and remove airborne hazardous or poisonous substances like gases, vapours, aerosols, and dust, protecting users from exposure to harmful chemicals. (d) Personal protective equipment (PPE) used in the laboratory. - Lab coats - safety glasses - respiratory protector - Hand gloves - Face shield

(a) Volume of pipette used = 25.00 cm\(^3\) Burette readings (cm\(^3\)) Rough 1st titre 2nd titre Final burette reading 20.90 40.90 21.00 Initial burette reading 0.00 20.10 0.00 Volume of acid, A used 20.90 20.80 21.00 Volume of A used = \(\frac{Rough + 1st titre + 2nd titre}{3}\) = \(\frac{20.90 + 20.80 + 21.00}{3}\) = 20.90 cm\(^3\) (b) 2HNO\(_3\)\(_{aq}\) + Na\(_2\)CO\(_3\).xH\(_2\)O\(_{aq}\) → 2NaNO\(_3\) + CO\(_2\) + (X+1)H\(_2\)0(l) c(i) concentration of E in moldm\(^{-3}\) Since we do not know the concentration of D in moldm\(^{-3}\), but in g per cm\(^3\), it will be difficult using the fomula \(\frac{C_A V_A}{C_B V_B}\) = \(\frac{N_A}{N_B}\). Thus, we must first convert the Conc. of D to moldm\(^{-3}\). We were told from the question that D contains 6.30 g of HNO\(_3\) in 500 cm\(_3\), So, if D 6.30 g of HNO\(_3\) was dissolved in 500 cm\(_3\) then, X g of HNO\(_3\) will be dissolved in 1000 cm\(_3\) X = \(\frac{{6.30}\times{1000}}{500}\) = 12.6 gdm\(^{-3}\) Recall that Molar concentration (moldm\(^{-3}\)) = \(\frac{Mass concentration(gdm^{-3})}{Molar mass}\) Molar mass od HNO\(_3\) = 1 + 14 + (16 X 3) = 63 g/mol concentration of D(moldm\(^{-3}\)) = \(\frac{Mass concentration(gdm^{-3})}{Molar mass}\) C\(_D\) = \(\frac{12.6}{63}\) = 0.20 moldm\(^{-3}\) Now we can use the formula \(\frac{C_D V_D}{C_E V_E}\) = \(\frac{N_D}{N_E}\). Given that C\(_D\) = 0.20 moldm\(^{-3}\) N\(_D\) = 2 V\(_D\) = 20.90cm\(^3\) N\(_E\) = 1 C\(_E\) = ? V\(_E\) = 25.0cm\(^3\) C\(_B\) = \(\frac{C_D V_D N_E}{N_D V_E}\) C\(_B\) = \(\frac{ 0.2 X 20.90 X 1}{25 X 2}\) = 0.0836 moldm\(^{-3}\) = 0.084 moldm\(^{-3}\) (ii) To get the value of x in Na\(_2\)CO\(_3\).xH\(_2\)O First, from the question, if 8.20 g of Na\(_2\)CO\(_3\).xH\(_2\)O was dissolved in 250 cm\(^3\) of distilled water. then, Xg of Na\(_2\)CO\(_3\).xH\(_2\)O will be dissolved in 1000 cm\(^3\) of distilled water. So, X = \(\frac{{8.20}\times{1000}}{250}\) = 32.8 gdm\(^{-3}\) Mass concentration of E = 32.8 gdm\(^{-3}\) Recall that concentration of E(moldm\(^{-3}\)) = \(\frac{Mass concentration(gdm^{-3})}{Molar mass}\) Then, Molar mass of E ( Na\(_2\)CO\(_3\).xH\(_2\)O ) = \(\frac{Mass concentration}{Molar concentration}\) = \(\frac{32.8}{0.0836}\) = 392.34 g/mol But Molar mass of Na\(_2\)CO\(_3\).xH\(_2\)O = Na\(_2\)CO\(_3\) + x(H\(_2\)O) 392.34 = (23 x 2) + 12 + (16 x 3) + 18x 392.34 = 46 + 12 + 48 + 18x 392.34 = 106 + 18x 18x = 392.34 - 106 18x = 286.34 x = \(\frac{286.34}{18}\) x = 15.9 x ≈ 16

F = (NH\(_4\))\(_2\)CO\(_3\) TEST OBSERVATION INFERENCE (a) F + t.t + dil. HCl Effervescence of colourless, odourless gas. Evolved gas turned lime water milky CO\(_2\) from CO\(_3\)\(^{2-}\) or HCO\(_3\) confirmed. b(i) 1st portion + t.t + NaOH in drops and then in excess + heat to warm No visible reaction, No ppt was also formed Effervescence of a colourless gas with an irritating smell. Gas turned red litmus to blue,also produced white fumes with conc. HCl NH\(_3\) from NH\(_4\)\(^+\) confirmed. (ii) 2nd portion + t.t + few drops of potassium hexacyano ferrate(II) solution No ppt formed and no visible reaction was observed Fe\(^{2+}\)/ Fe\(^{3+}\) absent

a(i) The chemical formula for alumina,(aluminium oxide) is Al\(_2\)O\(_3\) (ii) In the extraction of aluminium,the compound that is used; I. to obtain alumina from Bauxite - Sodium hydroxide, NaOH II. as solvent for alumina - Cryolite, Na\(_3\)AlF\(_6\) (iii) The electrodes used in the extraction of aluminium are - cathode (negative electrode) graphite, - anode (positive electrode) carbon rods or slabs. (iv)The extraction of aluminium is expensive due to the high energy requirements of the electrolysis process, which involves purifying bauxite, melting aluminium oxide, and using electricity to break down electrolytes. (v) In the extraction of aluminium: I. the substance liberated at the anode is oxygen gas (O₂) II. the equation for the reaction that leads to decrease in the size of the anode is: C + O\(_2\) → CO\(_2\) b(i) Ions that cause hardness of water are Ca\(^{2+}\) and Mg\(^{2+}\) (ii) Advantages of hard water - strengthening bones and teeth, - potentially aiding digestion, and - reducing the risk of cardiovascular disease. - improves the taste of water due to the presence of the ions. Disadvantages of hard water - skin and hair dryness, - reduced soap effectiveness, - potential appliance damage, and plumbing issues. c(i) Destructive distillation of coal is a process of heating coal in the absence of air (or with limited oxygen) to break down its complex molecules into simpler, useful products like coke, coal gas, coal tar, and ammoniacal liquor. (ii) products obtained from the destructive distillation of coal are: - coke - coal gas - coal tar and - ammoniacal liquor d(i) Gases which can be used to demonstrate the fountain experiment are; - Ammonia, NH\(_3\) - Hydrogen chloride gas, HCl (ii) Ammonia (NH\(_3\)) and hydrogen chloride (HCl) are used in the fountain experiment to demonstrate the high solubility of gases in water. When water is introduced into a flask containing either gas, the gas dissolves rapidly, creating a pressure drop that forces water upwards, forming a "fountain".

a(i) Salt solution is acidic - Reaction is exothermic. - White precipitate is likely to be a trioxocarbonate(IV) salt of Al, Ca and Zn. - Prepared solution contained soluble salt of Al, Ca and Zn. b(i)PbSO\(_4\) (ii) NaHCO\(_3\) (iii) NaHCO\(_3\) ; Cu(NO\(_3\))\(_2\). (iv) NaHCO\(_3\) (v) NH\(_4\)Cl (c) Precautions to be taken during titration include: - Wear a lab coat to protect your clothing from spills. - Ensure to rinse the burette with an acid solution - Also ensure the funnel is removed immediately after filling the acid into the burette. - Avoid error due to parallax while taking the reading to determine the end point. - Ensure all glassware is clean and free of bubbles.

The dehydration of ethanol is a chemical reaction that produces ethene and water from ethanol: The chemical equation for the dehydration of ethanol is: CH\(_3\)CH\(_2\)OH + H\(_2\)SO\(_4\) → CH\(_2\)=CH\(_2\) + H\(_2\)O The reaction is performed by heating ethanol with concentrated sulfuric acid at around 170^\circC. Sulfuric acid is a dehydrating agent, meaning it absorbs water.

a(i) Salt solution is acidic - Reaction is exothermic. - White precipitate is likely to be a trioxocarbonate(IV) salt of Al, Ca and Zn. - Prepared solution contained soluble salt of Al, Ca and Zn. b(i)PbSO\(_4\) (ii) NaHCO\(_3\) (iii) NaHCO\(_3\) ; Cu(NO\(_3\))\(_2\). (iv) NaHCO\(_3\) (v) NH\(_4\)Cl (c) Precautions to be taken during titration include: - Wear a lab coat to protect your clothing from spills. - Ensure to rinse the burette with an acid solution - Also ensure the funnel is removed immediately after filling the acid into the burette. - Avoid error due to parallax while taking the reading to determine the end point. - Ensure all glassware is clean and free of bubbles.

When the temperature is decreased in a reversible reaction, the equilibrium shifts in the direction that produces heat (exothermic direction). For an exothermic reaction, this means the equilibrium position shifts to the right, favoring the forward reaction.

Radon is a radioactive noble gas and is produced as a decay product of uranium and thorium in the Earth's crust. It is colorless, odorless, and tasteless, making it potentially hazardous when it accumulates in enclosed spaces.

The phase change from a liquid to a gas involves an increase in entropy. In the gas phase, molecules have higher degrees of freedom and are more dispersed compared to the liquid phase, resulting in higher entropy change.

The sum of the oxidation numbers in a neutral compound is always zero. This is because oxidation numbers represent the charge that an atom would have if all bonding were ionic. In a neutral compound, the total positive charge (from the oxidation numbers of the atoms that have positive oxidation numbers) must equal the total negative charge (from the atoms that have negative oxidation numbers).

In the kinetic theory of gases, the pressure exerted by a gas is a result of the frequent and random collisions of gas particles with the walls of the container. The force of these collisions creates pressure on the container walls.

Eutrophication is the excessive growth of algae and aquatic plants in water bodies due to the increased availability of nutrients like nitrogen and phosphorus. This nutrient enrichment often comes from agricultural runoff, sewage, and industrial discharges.

The industrial production of ammonia is known as the Haber process. It involves the reaction of nitrogen gas (N\(_2\)) and hydrogen gas (H\(_2\)) at high temperature and pressure in the presence of a catalyst to produce ammonia (NH\(_3\)).

Both Rutherford and Bohr contributed to the planetary model of the atom, but it was Rutherford who initially proposed the idea of electrons orbiting the nucleus. Rutherford's model, however, had limitations in explaining the stability of the atom. Later, Niels Bohr refined Rutherford's model by introducing the concept of quantized energy levels and stable orbits for electrons.