Question TRIAL PRE PSPM I 2020 CHEMISTRY MATRICULATION , MALAYSIA PDF

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KOLEJ MATRIKULASI PERAK KEMENTERIAN PENDIDIKAN MALAYSIA

PRA PEPERIKSAAN SEMESTER PROGRAM MATRIKULASI PRE PSPM SEMESTER 1 SESI 2020/2021 SEMESTER 1 SESSION 2020/2021

KIMIA SK015 Dua Jam Chemistry SK015 Two hours

JANGAN BUKA KERTAS SOALAN INI SEHINGGA DIBERITAHU DO NOT OPEN THIS QUESTION PAPER UNTIL YOU ARE TOLD TO DO SO

Kertas soalan ini adalah SULIT This question paper is CONFIDENTIAL

LIST OF SELECTED CONSTANT VALUES Speed of light in a vacuum, c = 3.0 x 10-8 m s-1 Avogadro’s number , NA = 6.02 x 1023 mol-1 h = 6.6256 x10-34 J s

Planck constant, Rydberg constant,

RH

= 1.097x 107 m-1 = 2.18x 10-18 J

Molar volume of gases , Vm = 22.4 dm3 mol-1 at STP = 24 dm3 mol-1 at room temperature Ionisation constant for water at 250C, Kw = 1 x 10-14 mol2 dm-6 Molar of gases constant, R = 8.314 J K-1 mol-1 = 0.08206 L atm mol-1 K-1

PRE-PSPM 1 80 MARKS Answer all questions

1. (a)

(b)

An aqueous solution contains 167 g CuSO4 in 820 mL of solution. The density of the solution is 1.195 gmL-1. Calculate: (i) percentage by mass of CuSO4. (ii) molarity of the solution. [7 marks] Methyl alcohol, CH 3OH, is produced via the reaction CO (g)

+

2H2 (g)

→

CH3OH (l)

A mixture of 1.20 g H 2 and 7.45 g of CO are allowed to react. (i) Determine the limiting reactant. (ii) What is the maximum amount (in grams) of CH3OH that can be obtained? (iii) Calculate the mass of excess reactant that is left after the completion of the reaction. [10 marks] 2. (a)

(b)

3. (a)

The Balmer series of the emission spectrum of hydrogen atom contains a line with a wavelength of 486.4 nm. (i) Calculate the frequency of this line. (ii) Determine the electron transition associated with this line. (iii) State the region of the electromagnetic spectrum in which this line is found. [7 marks] The proton number of calcium, Ca, is 20. (i) Write the electronic configuration of Ca atom. (ii) Write the sets of quantum numbers for the valence electrons in Ca atom. (iii) Draw a shape of orbital occupied by the valence electrons in Ca atom. (iv) Write the orbital diagram of the most stable Calcium ion.

[5 marks]

Explain why PH 3 can form a dative covalent bond with H+ but not BH3.

[2 marks]

(b)

Write an equation to show the formation of BF4- from F- ion and BF3 molecule by using Lewis symbol. Name the type of bond formed. [4 marks]

(c)

Phosgene, COCl 2, is a colourless, highly toxic gas employed against troops in World War I and is used today as a key reactant in organic synthesis. (i) Draw all possible Lewis structures for phosgene. Then, identify the most plausible structure and explain. (ii) Determine the molecular shape and polarity of phosgene. [9 marks]

4. (a)

A sample of zinc metal reacts completely with excess hydrochloric acid. Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g) The hydrogen gas produced is collected over water at 25 0C. The volume of the gas collected is 7.70 L and the atmospheric pressure is 0.98 atm. Calculate the amount of zinc metal consumed in the reaction. Given vapour pressure of water at 25 0C is 23.8 mmHg. [7 marks]

(b)

(i) The following table shows the boiling point of several liquids. Arrange these liquids in order of increasing vapour pressure. Explain. O

Liquid

Boiling point/ 0C

CH 3CH Ethanal, 20

Ethanol, CH3CH2OH

Methanol, CH3OH

78

55 [3 marks]

(c)

5. (a)

State a difference between amorphous and crystalline solid

Calculate the equilibrium constant, Kp, for the reaction. N2O4 (g) 2NO2 (g) Given Kc is 0.126 at 160 0C.

(b)

[2 marks]

[3 marks]

At 720 0C, the equilibrium constant, Kc for the reaction below is 2.37 x 10-3. N2 (g) + 3H2 (g) 2NH3 (g) In a certain experiment, the concentrations for N 2, H2 and NH3 are 0.683 M, 2.20 M and 1.05 M respectively. Is the system at equilibrium? Explain. [5 marks]

(c)

Consider the following equilibrium system H2O (g) + C(s) CO(g)

+

H2 (g)

State the effect on the amount of CO and the value of Kc if the following changes were made after the system had attained equilibrium. (i) Increasing pressure. (ii) More steam added. [4 marks]

6. (a)

Give the conjugate acid for the following bases (i) CN(ii) HCO3-

[2 marks]

(b)

Calculate the [H+] and [OH-] of human blood at pH 7.40 at 250C.

[2 marks]

(c)

Calcium sulphate, CaSO4, is a partially soluble compound with Ksp = 2.0 x 10-4 (i) Calculate the molar solubility of CaSO4 in pure water. (ii) Calculate the molar solubility of CaSO4 in 0.2 M calcium chloride, CaCl2 solution. (iii) Explain the differences in the molar solubility value calculated from (i) and (ii) [8 marks]

END OF QUESTION PAPER...