Get premium membership and access revision papers, questions with answers as well as video lessons.

Dce0016:Chemistry Question Paper

Dce0016:Chemistry

Course:Diploma In Civil Engineering

Institution: Meru University Of Science And Technology question papers

Exam Year:2014

INSTRUCTIONS: Answer questions one and any other two questions
QUESTION ONE – (30 MARKS)
(a) Give mathematical expression for
(i) Molarity
(ii) Molality (4 Marks)
(b) Describe the Arrhenius theory of
(i) An acid
(ii) Base (4 Marks)
(c) John Dalton proposed his atomic theory of matter. State four postulates that were
proposed by Dalton. (4 Marks)
(d) State factors that influence the physical behaviour of a gas. (4 Marks)
(e) Give the three fundamental particles of matter. (3 Marks)
(f) Identify the quantum numbers that:
(i) Describe the electron’s relative energy
(ii) Describes the geometrical shape of the electron cloud
(iii)Limits the number of electrons in any given orbital. (6 Marks)
(g) Draw the shape of water molecule and show the position of the non-bonding electrons.
(3 Marks)
(h) Complete the nuclear equation given below. (2 Marks)
?? + ?? ??+ ?? 0
1 1 3
1 2
+ ???????????? (2 Marks)
QUESTION TWO – (15 MARKS)
(a) (i) Define the term “mole fraction” (2 Marks)
2
(ii) A solution is composed of 36 gm water and 46gm ethanol, (??2??5????). Calculate the
mole fraction of each component of the mixture. (6 Marks)
[H = 1, C = 12, O = 16]
(b) A buffer solution was prepared by mixing 200cm3 of 0.6M ammonia solution and
300cm3of a 0.3M ammonium chloride solution to make 500cm3 final volume of the
mixture.
(i) Calculate the molar concentration of each of Ammonia and Ammonium Chloride
added to the solution to make the buffer. (3 Marks)
(ii) Ammonia and water reacts and establishes the following equilibrium.
NH3 + H2O ? NH4
+ + OH-, Kb = 1.8x10-5 and given that H+ [OH-]
= 1.0X10-14 Calculate the pH of the buffer in b(i) above.
(4 Marks)
QUESTION THREE – (15 MARKS)
(a) (i) What type of radiation is emitted by radioactive substances? (3 Marks)
(ii) Define the term half-life in reference to radioactive decay. (2 Marks)
(iii) A chemist established that after exactly 7days, his initial 10.0??g of 222Rn sample had
decayed to 2.82??g of randon 222Rn. What is the rate constant for the ? -decay of 222Rn?
(3 Marks)
(iv) Calculate the half-life of 222Rn (3 Marks)
(b) State four applications of radioactivity (4 Marks)
QUESTION FOUR – (15 MARKS)
(a) With the aid of a diagram, describe the electron-sea model in metallic bonding.
(4 Marks)
(b) What are the physical properties associated with the metallic bonding? (4 Marks)
(c) The line at 434nm wavelength in the Balmer series of hydrogen spectrum corresponds to
transition of an electron from the nth to the second Bohr orbit, what is the value of n,
given that (6 Marks)
?? = 3.2881??1015??-1
1
22 -
1
??2 and ?? = 2.9979??108????-1, 1m=1.0 x 109nm.
(d) In what portion of the electromagnetic spectrum will this series be found? (1 Mark)

Dce0016:Chemistry Question Paper

More Question Papers

Popular Exams