UAS 22-23 FAD1018 Basic Chemistry II
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FAD1018
The phase diagram of water is shown below.
[Phase diagram graph with vertical y-axis labeled "Pressure" and horizontal x-axis labeled "Temperature". Three equilibrium curves meet at a triple point. Points labeled: S in the upper-left region, P on the solid-liquid equilibrium line, Q on the liquid-vapour equilibrium line, and R in the lower-right region.]
(i) Starting from S, indicate the phase transitions needed to reach R. (ii) Which curve indicates the equilibrium between liquid and vapour phases? (iii) What does point Q represent?
(3 marks)
- Untuk molekul di bawah;
[Structural formula showing a molecule with two adjacent carbon atoms bonded vertically. The top carbon is bonded to OH (upward), H (solid wedge to upper right), CH₃ (dashed wedge to upper left), and the bottom carbon. The bottom carbon is bonded to HO (solid wedge to lower left), H (downward), CH₃ (to the right), and the top carbon.]
(i) lukis imej cerminnya. (ii) tandakan pusat kiral dengan asterisk (*). (iii) nyatakan hubungan antara molekul ini dan imej cerminnya dalam (i).
(3 markah)
For the following molecule;
[Same structural formula as above: two adjacent carbons in a vertical chain. Top carbon bonded to OH (upward), H (solid wedge to upper right), CH₃ (dashed wedge to upper left), and bottom carbon. Bottom carbon bonded to HO (solid wedge to lower left), H (downward), CH₃ (to the right), and top carbon.]
(i) draw its mirror image. (ii) indicate the chiral center using asterisk ().* (iii) state the relationship between the molecule and its mirror image in (i).
(3 marks)
3/13
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FAD1018
- Kenal pasti semua bahan uji dan/atau keadaan tindak balas bagi proses A – E dalam tindak balas berikut:
[Reaction scheme. Left column: top structure is an alkene (pent-2-ene skeletal structure), arrow A pointing down to an aldehyde (butanal/propanal skeletal structure with terminal C=O), arrow D pointing down to a primary alcohol (corresponding skeletal structure with terminal OH). Right column: top structure is a nitrile (skeletal structure with terminal CN), arrow B pointing down to a carboxylic acid (skeletal structure with terminal COOH), arrow E pointing down to an amide (skeletal structure with terminal CONH₂). Arrow C points horizontally from the aldehyde to the carboxylic acid.]
(5 markah)
Identify all the reagents and/or reaction conditions for the processes of A – E in the following reaction:
[Same reaction scheme repeated: alkene →(A) aldehyde →(D) alcohol on the left; nitrile →(B) carboxylic acid →(E) amide on the right; aldehyde →(C) carboxylic acid horizontally.]
(5 marks)
4/13
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(a) Dinitrogen tetroxide, $N_2O_4$ is a highly toxic and corrosive oxidising agent. The decomposition of $N_2O_4$ into nitrogen dioxide, $NO_2$ is shown in the equation below.
$$N_2O_4(g) \rightleftharpoons 2NO_2(g) \qquad \Delta H = 55.3 \text{ kJ}$$
An amount of 0.80 mol of $N_2O_4$ was introduced into a 2.0 L sealed vessel at 300 K. It is given that the equilibrium constant, $K_c$ value for the reaction is $4.6 \times 10^{-3}$. Calculate the number of moles of both gases when equilibrium has been attained and state the effect on equilibrium position if the reaction at equilibrium is carried out at lower temperature. (6 marks)
(b) Draw and label a schematic diagram of an electrolytic cell containing molten calcium chloride salt as the electrolyte. If a current of 6 A is passed through that cell for 3.4 hours, calculate the mass of calcium solid (in gram) which will be deposited at the electrode. (RAM: $Ca = 40.0$, $Cl = 35.0$; $1 F = 96500$ C) (9 marks)
11. (a) (i) Lakar gambar rajah fasa takat-didih komposisi bagi sistem dua komponen larutan unggul heksana dan heptana. Takat didih bagi heksana dan heptana masing-masing adalah 69 dan 98 °C. (ii) Larutan manakah yang akan terkumpul dalam kelalang penerima? Jelaskan jawapan anda secara ringkas. (6 markah)
(b) Kitaran Born-Haber adalah kaedah yang berguna untuk memahami pembentukan sebatian ionik seperti magnesium fluorida, MgF$_2$, kerana ia menunjukkan pelbagai langkah yang terlibat dalam pembentukan sebatian tersebut. Dengan menggunakan data berikut;
[Table with two columns: "Entalpi" and "kJ mol$^{-1}$"]
| Entalpi | kJ mol$^{-1}$ |
|---|---|
| Afiniti elektron pertama bagi fluorin | $-328.0$ |
| Entalpi pengatoman bagi fluorin | 75.3 |
| Tenaga pengionan pertama bagi magnesium | 736.0 |
| Entalpi pengatoman bagi magnesium | 148.0 |
| Tenaga pengionan kedua bagi magnesium | 1450.0 |
| Entalpi pembentukan bagi magnesium fluorida | $-594.1$ |
(i) lukis kitaran Born-Haber bagi pembentukan MgF$_2$ dan label semua perubahan tenaga yang berkaitan. (ii) tentukan tenaga kekisi bagi MgF$_2$. (9 markah)
7/13
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(a) (i) Sketch the boiling point – composition diagram for a two-component ideal solution of hexane and heptane. Boiling points of hexane and heptane are 69 and 98 °C, respectively. (ii) Which solution is collected in the receiving flask? Briefly explain your answer. (6 marks)
(b) The Born-Haber cycle is a useful method to understand the formation of ionic compounds like magnesium fluoride, MgF$_2$, as it shows the various steps involved in the formation of the compound. By using the following data;
[Table with two columns: "Enthalpy" and "kJ mol$^{-1}$"]
| Enthalpy | kJ mol$^{-1}$ |
|---|---|
| First electron affinity of fluorine | $-328.0$ |
| Enthalpy of atomisation of fluorine | 75.3 |
| First ionisation energy of magnesium | 736.0 |
| Enthalpy of atomisation of magnesium | 148.0 |
| Second ionisation energy of magnesium | 1450.0 |
| Enthalpy of formation of magnesium fluoride | $-594.1$ |
(i) draw a Born-Haber cycle for the formation of MgF$_2$ and label all the relevant energy changes. (ii) determine the lattice energy of MgF$_2$. (9 marks)
12. (a) (i) Molekul yang ditunjukkan di bawah adalah contoh pewarna azo. Tunjukkan semua bahan tindak balas, bahan uji dan keadaan yang diperlukan untuk mensintesis sebatian ini.
[Chemical structure diagram: An azo dye molecule consisting of three fused/connected aromatic rings. Left side: a naphthalene ring system (two fused benzene rings) with an HO— group attached to one position. Connected via an azo group (—N=N—) to a benzene ring on the right side, which has an —NO$_2$ group (nitro group) attached to it.]
(ii) Asetik anhidrida, C$_4$H$_6$O$_3$ digunakan sebagai kumpulan pelindung untuk urutan sintesis peptida. Tunjukkan urutan sintesis jika asid 2-amino-4-metilpentanoik bertindak balas dengan asetik anhidrida, diikuti oleh asid 2-aminopropanoik (6 markah)
8/13
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FAD1018
(b) Write the molecular structures of all the main compounds $U - Z$ for the following reaction:
[Reaction scheme diagram]
$$\text{CH}_3\text{CH}_2\text{Cl} \xrightarrow[\Delta]{\text{NaOH (aq)}} U \xrightarrow[\Delta]{\text{K}_2\text{Cr}_2\text{O}_7, \text{H}^+} V$$
$$\begin{array}{c|c|c} \downarrow & \downarrow & \downarrow \ \text{1. Mg, ether} & \text{1. 4NaOH, 3I}_2 & \text{CH}_3\text{CH(OH)CH}_3 \ \text{2. CO}_2 & \text{2. H}_3\text{O}^+ & \text{H}_3\text{O}^+ \ \text{3. H}_3\text{O}^+ & & \Delta \ \end{array}$$
$$\begin{array}{ccc} W & X & Y \ & \downarrow & \ & \text{KMnO}_4, \text{H}^+ & \ & \Delta & \ & Z & \ \end{array}$$
(6 marks)
TAMAT/END
13/13
Verbatim transcription via Kimi K2.6 vision subagents.