chemistry questionnaire essay

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What is supposed by the term cis-trans isomerism? How a large number of cis-trans isomers are present in Structure I? Draw virtually any 2 feasible cis-trans isomers. (iii) Express the physical state on this lipid in room temp. Explain the answer. [9] (b) Suggest a possible identification for each in the organic chemical substances A-E listed below. Explain your reasoning and write well balanced equations for the reactions involved wherever possible. i) A, C11H14O2 is a natural compound. Hydrolysis of A gives B, C7H6O2 which is a white precipitate and C, C4H10O which will not decolourise acidified potassium manganate(VII) on heating.

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(ii) Deb, C4H10O2 acts with two moles of sodium material, but not with solid salt carbonate. On boiling below reflux with aqueous potassium manganate(VII), D gives a compound, E, C4H6O3. E acts with alkaline aqueous iodine to give a yellow medications and advances carbon dioxide when ever solid sodium carbonate is usually added.

Bring structural formulae of the products of the reactions between glutamic acid and i also aqueous NaOH II aqueous HCl (ii) Draw the structural formula of a dipeptide formed among glutamic acid and phenylalanine, showing the ionic kind in which it would exist in pH twelve.

[4] [Total: 20] 5 a few (a) Iron(III) chloride is a dark brown stable which dissolves in normal water to give a great acidic answer. This remedy is used to etch, i actually. e. melt, unwanted birdwatcher from branded circuit boards. When a copper-coated printed signal board is immersed in aqueous iron(III) chloride, the perfect solution is turns greenish blue. i) Explain, with an formula, why aqueous iron(III) chloride is acidulent. (ii) Utilize the Data Guide to explain why iron(III) chloride etches water piping. Give a relevant equation to explain the greenish blue solution observed. (iii) Suggest how it changes the overall E0 value in the event the thickness from the copper finish is improved.

Anhydrous aluminum chloride behaves similarly as anhydrous iron(III) chloride in that they classy readily once heated. Once 1 . 56 g of aluminium chloride was placed in an cleared out vessel of volume 1 . 00 dm3 at 1800C, the pressure produced was 32. kPa. (i) Estimate the evident relative molecular mass from the aluminium chloride under the stated conditions. (ii) In the vapour phase, aluminum chloride partially exists as a dimer. Using your answer acquired for b(i), calculate the percentage of the dimer under the explained conditions. (iii) Suggest grounds why the dimerisation procedure for aluminium chloride is exothermic. 6 (iv) Predict, providing a reason in each case, the effect on the proportion of dimer inside the equilibrium combination if I the pressure is lowered, II the heat is lowered.

MgO(s) & CO2(g)? They would? = +117 kJ mol-1;? S? = +175 L mol-1 K-1 8 (i) Why does the entropy maximize when magnesium (mg) carbonate decomposes? (ii) Calculate the standard Gibbs free energy transform,? G?, intended for the decomposition of magnesium (mg) carbonate. Discuss the spontaneity of the decomposition of magnesium carbonate in room temperatures. (iii) Let’s assume that? H? and? S? intended for the reaction happen to be independent of temperature, estimate the temp at which the decomposition response becomes possible. (iv) Evaluate the ease of heat decomposition of magnesium carbonate with ba (symbol) carbonate. [8] Turn over some (d) Suggest a simple chemical substance test to tell apart between each pair of substances. For each test, give reactants and conditions, and point out what would be seen with each mixture.

The dissociation reactions and Ka ideals of carbonic acid are given below. H2CO3 HCO3- & H+ Ka1 = 5. 2 by 10-7 mol dm-3 HCO3- CO32 ” + H+ Ka2 = 4. almost eight x 10-11 mol dm-3 0. 12 mol dm-3 aqueous NaOH is added slowly to twenty. 0 cm3 of carbonic acid plus the change in ph level is implemented and displayed below. pH x times B back button A x x twelve 20 30 40 12 Vol of aqueous NaOH added as well as cm3 (i) Calculate the original pH in the carbonic acid, stating any assumptions you choose. (ii) Compute the ph level at the 1st equivalence level, A. (iii) What is the pH for point W? Give a basis for your answer. [6] [Turn more than 5 (b) Maintenance of pH is vital towards the cells of living organisms because chemical activity is influenced by pH. For example, protection from harmful pH change in the blood plasma is given by the hydrogencarbonate/carbonic acid system (HCO3-/H2CO3). At 370C, the temperature in the human body, pH of blood plasma is definitely 7. 4. i) Make clear, with relevant equations, how the hydrogencarbonate/carbonic chemical p system regulates the ph level of bloodstream plasma. (ii) Calculate exactely [HCO3-]/[H2CO3] intended for maintaining the best pH of blood sang. [4] (c) Describe two differences in physical properties among transition precious metals and a s-block metal such as magnesium (mg), suggesting factors behind these variations based on their atomic buildings. [3] eleven (d) The oxidation of manganese(IV) oxide in alkaline solution in air produces green manganate(VI) ion, MnO42-. When manganate(VI) is included in a dilute acid, a purple answer and dark brown solid manganese(IV) oxide reforms.

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