STPM SEM 1 Quiz 2

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

• 15

• 30

• 60

• 100

• 0.14 mol² dm^-6

• 1.80 mol² dm^-6

• 3.52 mol² dm^-6

• 4.48 mol² dm^-6