CH 110 2

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Copperbelt University *

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INORGANIC

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Chemistry

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Nov 24, 2024

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pdf

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6

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Page 1 of 6 QUESTION ONE: ORGANIC CHEMISTRY 1. Draw the structural formulas for the following compounds: [3] a) 3,3,6,6-tetramethyl-4-octyne b) 2-bromo-1-tert-butylcylopropane c) 3-ethyl-2, 3-dimethyl-2-pentanol 2. Draw any two possible structures for the following molecular formula and name them ? 5 𝐻 12 ? [2] 3. Answer the following question on aromatic compounds [3] a) Identify the import characteristics of an aromatic compound b) What is the major property given the reagent below? 4. Draw the structure of the compound with three carbon atoms that belongs to each of the following families of organic compounds: [4] a) Aldehydes b) Ketones c) Carboxylic acids d) Ether 5. Give the structure of the product(s) resulting from the oxidation of each of the following alcohols/aldehydes and name them: [3] a) 3-methyl-2-butanol b) 2-methyl-2-butanol c) 2-methylcyclopentanol 6. Draw the structure of the major products for each of the following reactions: [3] a) ?𝐻 3 ?𝐻 2 ?𝐻 = ?𝐻 2 + 𝐻 2 ? ?? b) ?𝐻 3 ?𝐻 2 ?𝐻 = ?𝐻 2 + ?? c) ?𝐻 3 ?𝐻 2 ?𝐻 = ?𝐻 + 2𝐻?? 7. What carboxylic acid and alcohol are required to produce the following ester? [1] 8. Complete the following esterification reaction: [1] [20 TOTAL MARKS]
Page 2 of 6 QUESTION TWO: THERMOCHEMISTRY 1. State Hess’s law ? [2] 2. Consider the following reaction [3] 2?? (?) + ? 2(𝑔) → 2??? (?) ∆𝐻 = −1204 ?? i. Calculate the amount of heat transferred when 2.4g of ?? (?) reacts at constant pressure. ii. How many grams of ??? (?) are produced during an enthalpy change of ∆𝐻 = 96 ?? ? iii. How many Kilo joules of heat are absorbed when 7.50 g of ??? (?) are decomposed into ?? (?) 𝑎?? ? 2(𝑔) at constant pressure. 3. From the following enthalpies of reaction; [6] 𝐻 2 (𝑔) + 𝐹 2 (𝑔) → 2𝐻𝐹 (𝑔) ∆𝐻 = −537 ?? ? (?) + 𝐹 2 (𝑔) → ?𝐹 2 (𝑔) ∆𝐻 = −680 ?? 2? (?) + 2𝐻 (𝑔) → ? 2 𝐻 4(𝑔) ∆𝐻 = −52.3 ?? Calculate the ∆𝐻 for the reaction of ? 2 𝐻 4(𝑔) 4. Identify each process as endothermic or exothermic and indicate the sign of ∆𝐻 . [3] i. Sweat evaporating from skin ii. Water freezing in a freezer iii. Wood burning in fire 5. Write thermodynamic equations corresponding to the following description [3] i. The standard enthalpy of formation of iron (III) oxide at 298 k is -824.2 KJ/mole ii. The standard enthalpy change at 298K for the reaction between gaseous phosphorous trichloride and chlorine gas to give gaseous phosphorus pentachloride is -84.3 KJ iii. The standard enthalpy OF COMBUSTIONOF LIQUID ethanol is -1368 KJ/mole 6. When 6.5 g sample of solid NaOH dissolves in100.00g of water in a coffee-cup calorimeter, the temperature rises from 21.6 to 37.8 . Calculate the ∆𝐻 (in KJ/mole) for the solution process. (Assume the specific heat of the solution formed is 4.18 J/g-K) ?𝑎?𝐻 (?) → ?𝑎 (𝑎?) + + ?𝐻 (𝑎?) [3] [20 TOTAL MARKS] QUESTION THREE: INTRODUCTION AND ATOMIC STRUCTURE 1. Bellow: [9] i. State the Five Steps involved in Scientific method. ii. Distinguish between extensive and intensive properties of matter
Page 3 of 6 iii. Perform Mathematical operations and express each result to the correct number of significant Figures a) 0.1054 + 2.07 − 2.114 b) 8.27(4.987 − 4.962) c) As part of a lab assignment to determine the value of the gas constant (R), a student measured the pressure (P), volume (V), and temperature (T) for a sample gas, where 𝑅 = ?𝑉 𝑇 . The following values were obtained: P=2.560, T=275.15 and V=8.8, Calculate R to the current number of significant figures. 2. Complete the table [5] S No. n I Subshell name Possible m value Number of orbitals (a) 3 2 (b) 2s 1 (c) 5 1 (d) 4 4f 3. one application of the wave- particle duality of matter is electron diffraction, which is used to determine the distances between atoms in crystalline Solids. Experimentally, this is done by accelerating beam of electrons to the point where the wavelength of the electron beam is of the same order of magnitude as the distance between atoms (roughly 0.1- o. 5 nm). How fast would an electron need to be travelling in order to have 0.10m? wavelength of 0.1 nm [4] 4. (i) What is the energy of a photon of light, with Wavelength of 515mm? (ii) use the Rydberg equation to explain the election transition (or give n 1 and n₂) that leads to the of the spectral line mentioned in (i) assuming the emission is of a hydrogen atom. [2] [20 TOTAL MARKS] QUESTION 4: CHEMICAL BONDING 1. Indicate the number of valence electrons in the following [4] (I) Oxygen (II) Group I elements (III) Halogens (IV) An element with an electron configuration 1? 2 2? 2 2? 6 3? 2 3? 1 2. The equations for the heats of formation of Copper(I)Oxide, Cu 2 O and Copper(II)Oxide, CuO are: 2?? 2(?) + 1 2 ? 2 (𝑔) → ?? 2 ? (?) ; ∆𝐻°? = −166.7 ??/????
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Page 4 of 6 ?? (?) + 1 2 ? 2 (𝑔) → ?? ? (?) ; ∆𝐻°𝑖 = −155.2 ??/???? The first and second ionization energies of copper are 750 and 2000kj/mol respectively; its atomization energy is 339.3kj/mol. The atomization energy of Oxygen is 249.2kj/mol. The first and second electron affinity for Oxygen are -141kj/mol and 790.8kj/mol respectively. Draw the Born-Haber cycle and calcultate the lattice energies ( ∆𝐻 𝑙𝑎?? ) of the two oxides. [6] 3. Explain the in the boiling points for each of the following [2] i. 𝐻𝐹 (20℃) ii. ??? (−85℃) iii. ?𝑖?? (1360℃) 4. Draw the possible resonance structures for the isocyanate ion ( ??? ) and using formal charges determines which structure has greater contribution to the resonance hybrid. [4] 5. Complete the following table by indicating whether the given molecules are polar or non- polar, further, indicate what intermolecular forces exist in each given substance. [4] substance Polarity Intermolecular force Silicon tetrachloride Sulphur dioxide Carbon dioxide Ammonia [20 TOTAL MARKS] QUESTION FIVE: STOICHIOMESTRY & REACTIONS IN SOLUTION 1. Organic Compound Y contains carbon, hydrogen, oxygen and nitrogen. 0.132g of Y is burned completely in oxygen to produce 0.072g of water, 0.176g of Carbon dioxide and 0.028g of nitrogen. The molar mass of Y is 132g.mole -1 . Deduce the molecular formula for Y. Show how You arrived at your answer. [5] 2. Then Potassium Chromate (? 2 ??? 4 ) is added to a solution containing 0.500g Silver nitrate ???? 3 , Solid Silver Chromate ????? 4 is formed. Write a balanced chemical equation and find the percent yield if 0.455g of silver chromate is obtained. [5] 3. Given the following reaction; [5]
Page 5 of 6 ??? 4 + ? 2 ? 3 2− → ?? 2 + ??? 2 i. identify the oxidizing and reaction reducing agents ii. Write the two half reaction equations specifying Which one is the Oxidation half reaction and which one is the reduction half reaction iii. Balance reach of the two half reaction equations iv. Considering that the reaction is taking place in a basic Medium, Write the overall balanced equation for this redox reaction. [20 TOTAL MARKS] QUESTION SIX: GASSES 1. state each of the following gas [5] i. Avogadro's law ii. charle's law iii. Boyle's low iv. Graham's law on diffusion of gasses. v. Dalton's partial pressure of a gas. 2. Three gasses were to were added to the Some container of Volume 20 litres to give a total pressure of 150 Kpa at 25°c. If the mature contained 8.0g of O 2 , 8.0g CO 2 and an unknown mass of N 2 . [9] i. Define the term Partial pressure ii. Calculate the partial pressure of each gas iii. Calculate the more fraction of each gas. iv. Determine the mass of N 2 in the container 3. GIVE any three pros postulates of the kinetic theory of gases. [3] 4. What is in volume, in litres of N 2 required to react with 18.6g of Magnesium at a temperature of 303K and pressure of 1.20 atm? [3] [20 TOTAL MARKS] QUESTION SEVEN: CHEMICAL EQUILIBRIUM 1. Calculate the value of the equilibrium constant, ? 𝑐 at 127°C for the reaction given below. 1 2 ? 2 (𝑔) + 3 2 𝐻 2 (𝑔) ⇄ ?𝐻 3(𝑔) Were; [?𝐻 3 ] = 3.1 × 10 −2 ???/? [𝐻 2 ] = 3.1 × 10 −3 ???/? [ ? 2 ] = 8.5 × 10 −1 ???/? [2]
Page 6 of 6 2. For the reaction for the formation of nitrogen: chloride 2?? (𝑔) + ?? 2 (𝑔) ⇄ 2???? (𝑔) [4] 𝑇ℎ? ?????????? ???? : ? ??𝐶𝑙 = 1.2 𝑎?? ? ?? = 5.0 × 10 −2 𝑎?? ? 𝐶𝑙 2 = 3.0 × 10 −1 𝑎?? i. Calculate ? ? 𝑎? 25℃ ii. Using ? ? calculate at (i), obtain the value of ? 𝑐 𝑎? 25℃ for the 2?? (𝑔) + ?? 2 (𝑔) ⇄ 2???? (𝑔) 3. Answer the questions below; [5] i. Write the reaction quotient for the reaction ? 2 (𝑔) + 3𝐻 2 (𝑔) ⇄ 2?𝐻 3 (𝑔) ii. For the synthesis of ammonia at 500°?, ? 𝐿 = 6 × 10 −2 Predict the direction in which the system will shift to reach equilibrium in the following cases a) [?𝐻 3 ] 0 = 1.0 × 10 −3 ? ; [? 2 ] 0 = 1 × 10 −6 ? ; [𝐻 2 ] 0 = 2.0 × 10 −3 ? b) [?𝐻 3 ] 0 = 2.0 × 10 −4 ?; [? 2 ] 0 = 1.5 × 10 −5 ? ; [𝐻 2 ] 0 = 3.54 × 10 −1 ? c) [?𝐻 3 ] 0 = 1.0 × 10 −4 ? ; [? 2 ] 0 = 5 ? ; [𝐻 2 ] 0 = 1.0 × 10 −2 ? 4. The reaction for the formation of gaseous hydrogen fluoride from hydrogen and flouride has ? 𝑐 = 1.1 ?10 2 at a certain temperature. In one experiment 3 moles of each components was added to the 1.5 litre flask. Calculate the equilibrium concentration of all species. [5] 5. Answer the questions below [4] i. state Le chaterlier's principle ii. Arsenic can be extracted from the ores first reacting the ore with oxygen (called roasting) to form ?? 4 ? 6 which is then reduced by Carbon ?? 4 ? 6 (?) + 6? (?) ⇌ ?? 4 (𝑔) + 6?? (𝑔) In which direction will the equilibrium position shift in response the following conditions, (1) Addition of carbon monoxide (2) Addition removal of carbon or tetra arsenic hexoxide ?? 4 ? 6 (?) (3) Removal of gaseous arsenic ( ?? 4 (𝑔) ) [20 TOTAL MARKS]
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