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WorksheetsSTPM SEM 1 Quiz 2
Total questions: 20
Worksheet time: 10mins
Chlorine consists of two isotopes; 35Cl and 37Cl in the ratio 3:1. Phosphorous is monoisotopic, 31P. A sample of phosphorous trichloride, PCl3, is analysed in the mass spectrometer. Part of the mass spectrum consists of three lines with m/e of 101, 103 and 105. Which of the following diagram best represent the relative abundance of the three lines?
A
B
C
D
Which of the following diagrams represent that of the Balmer series in the atomic emission spectrum of hydrogen?
A
B
C
D
The valence electrons of a bromine atom located in
a 4s orbital only
a 4p sub-shell only
4s and 4p sub-shell
4s, 4p and 4d sub-shells
Which of the following is most likely to be a linear molecule?
H2S
NO2
SCl2
ICl2
Under suitable conditions, xenon forms the XeF4 molecule. What is the shape of the XeF4 molecule?
Tetrahedron
Square planar
Octahedron
Pyramidal
Fullerene, C60, is one of the carbon allotropes found in soot. Which statement about fullerene is true?
It is used in carbon dating
Its carbon atoms undergo sp2 hybridisation
Its C-C bond length is the same as that of diamond
Its molecule does not have delocalised electrons
The kinetic data for reaction P + Q ---> R + S is shown in the table.
What is the rate law for the reaction?
Rate = k [P]2
Rate = k [Q]2
Rate = k [P][Q]2
Rate = k [P]2[Q]
The hydrolysis of 2-chloro-2methylpropane by aqueous sodium hydroxide is a first order reaction overall. The unit for the rate constant is
mol-1
mol
s-1
s
When the system Cl2(g) + PCl3(g) ↔ PCl5(g) is in equilibrium at a temperature of 6000C and 1 atm pressure, the value of the equilibrium constant, Kp is 30. What is the value of Kp at a pressure of 2 atm at the same temperature?
15
30
60
100
At temperature T K, ammonia disscociates into nitrogen and hydrogen gases.
2NH3(g) ↔ N2(g) + 3H2(g)
A mixture of 1.52 mol NH3(g) and 0.48 mol N2(g) was heated to a temperature T 0C in a 1.0 dm3 flask. If 0.66 mol NH3(g) is present at equilibrium, what is the equilibrium constant Kc for this reaction at T 0C?
0.14 mol2 dm-6
1.80 mol2 dm-6
3.52 mol2 dm-6
4.48 mol2 dm-6
What is the acid or base nature of an aqueous solution of ammonium fluoride?
[ Ka for NH4+ = 5.6 x 10-10 mol dm-3, Kb for F- = 1.4 x 10-11 mol dm-3 ]
Strongly acidic
Weakly acidic
Weakly basic
Neutral
A buffer solution contains equimolar quantities of HX and X -. If the pKb for X – is 6.0, what is the pH of the buffer solution?
2
6
8
10
Which of the following is true with regard to the ammonia molecule?
It is a non-polar molecule.
It has a trigonal planar shape
It contains two lone pairs of electrons.
The H─N─H bond single is 107°.
In the reaction: Cu2+ + 4NH3 → [Cu(NH3)4]2+, the Cu2+ ion acts as a
Lewis acid
Lewis base
Bronsted-Lowry acid
Bronsted-Lowry base
What is the pH of the solution formed when excess ammonium chloride is shaken with aqueous ammonia of concentration 0.1 moldm-3?
[The base dissociation constant of ammonia is 1.8 X 10-5 mol dm-3]
1 to 4
4 to 7
7 to 11
11 to 14
The boiling points of water and ammonia are 373K and 240K respectively. Which of the following statements best explains why the boiling point of water is higher than the boiling point of ammonia?
Oxygen is more electronegative than nitrogen.
The hydrogen bonds between water molecules are stronger than the hydrogen bonds between ammonia molecules.
The bond between oxygen and hydrogen is stronger than the bond between nitrogen and hydrogen.
There is van der Waals forces between water molecules but not between ammonia molecules.
The electronic configuration of an element Q is 1s2 2s2 2p6 3s2 3p6 3d1 4s2. Which of the following are correct regarding Q?
I. The number of valence electrons of Q is 2.
II. The proton number of element Q is 21.
III. The atom of Q has four energy levels that are filled with electrons.
I and II only
I and III only
II and III only
I, II and III
A quantity of 28 g of nitrogen is mixed with 32 g of oxygen at 298 K and 101 kPa. Which statement best describes the mixture of gases formed?
More oxygen than nitrogen molecules are found in the mixture.
The average kinetic energies of nitrogen and oxygen molecules are the same.
The average velocities of nitrogen and oxygen molecules are the same.
There is no transfer of kinetic energy when nitrogen and oxygen molecules collide.
An aqueous solution of a monobasic acid has pH 3.5. A 25.00cm3 volume of an aqueous solution of the acid is completely neutralized by 27.50cm3 of an 0.10moldm-3 sodium hydroxide solution. The value of the dissociation constant of the acid is
3.16 X 10-4 mol dm-3
3.48 X 10-5 mol dm-3
9.08 X 10-7 mol dm-3
9.99 X 10-8 mol dm-3
Which of the following statements is true of the hydrogen line spectrum?
The number of lines in each series is the same.
The lines in a series become closer when the frequency decreases.
The first line in each series has the lowest frequency.
The ionisation energy of hydrogen can be calculated from the frequency of the first line of the Lyman series.
