Sch2107:Inorganic Chemistry I Question Paper
Sch2107:Inorganic Chemistry I
Course:Bachelor Of Science In Public Health
Institution: Meru University Of Science And Technology question papers
Exam Year:2014
The following physical constants may be useful
Avogadros number (NA) = 6.023 × 1023 Rydberg’s constant, RH = 1.097 × 107??-1 Plank’s constant, h = 6.63 × 10-34???? Mass of an electron, me = 9.109 × 10-31???? Charge of an electron = 1.602 × 10-19?? Mass of a proton, mp = 1.673 × 10-27???? Velocity of light in vacuum = 2.99 × 108????-1
QUESTION ONE (30 MARKS)
a) State Pauli’s exclusion principle and use the atom of helium atom to illustrate it. (He=2). (4 Marks) b) Explain the meaning of the following terms; i. Mass number ii. Frequency iii. Molality iv. Nuclear fission (4 Marks) c) Draw the shapes of 2s, 2p and 3d orbitals. (6 Marks) d) Using the inert gas core, write electronic configurations of the elements whose atomic numbers are 11, 24, 17. State the period and group to which each element belongs. (8 Marks)
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e) An atom emits a photon of wavelength 550nm. Calculate the energy emitted by the atom in kJ/mole. (4 Marks) f) Caffeine (C8H10N4O2) is a natural compound which has applications in food industry and in pharmaceuticals. Calculate the percentage composition of caffeine. (C=12.01, H=1.008, N=14.01, O=16.00). (4 Marks)
QUESTION TWO (20 MARKS)
a) i) Define the term lattice energy of an ionic solid. (2 Marks) ii) The formation of NaCl(s) solid is shown by the equation indicated below. Na(s)+ ½ Cl2(g) NaCl(s) ????? 0 = -411????/??????
b) Study the equation of the chemical reactions (1-4) shown below and calculate the lattice energy of NaCl(s) (12 Marks) 1. Na(s) Na(g) ???1 = +108????/?????? 2. Na(g) Na+(g) +e- ???2 = +496????/?????? 3. ½ Cl2(g) Cl(g) ???3 = +121????/?????? 4. Cl + e- Cl-(g) ???4 = -357????/??????
c) Write the Lewis structures of the compounds indicated below showing the valence electrons only and indicating resonance structures where applicable. i. PH3 ii. SiO2 iii. SO2 (6 Marks)
QUESTION THREE (20 MARKS)
a) Explain the difference between molecular mass and molar mass. (4 Marks) b) 12.2g of sulphuric acid are dissolved in 198g of water to make a solution. Assuming that the density of water is 1000gL-1, calculate; i. Molarity of sulphuric acid solution. (4 Marks) ii. The molality of sulphuric acid solution. (4 Marks) iii. The mole fraction of the sulphuric acid in the solution. (4 Marks) c) i) Using an appropriate illustration, explain the term ionization energy. ii) The first ionization energies for the elements; sodium, magnesium, fluorine and chlorine are: 496,737,1681 and 1255kJ/mole respectively. Explain the differences between the pairs; Sodium and magnesium; fluorine and chlorine. (4 Marks)
QUESTION FOUR (20 MARKS)
a) Explain the meaning of the terms given below; i. Nucleons ii. Gamma (??) emission iii. Parent and daughter, as used in radioactivity. iv. Half – life (8 Marks)
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b) Write balanced equations for the following nuclear reactions by identifying the species represented by the letters M, N, O, R. i. ???? 3 6 + ?? 0 1 ? ?? 1 3 + ?? ii. ?? 1 3 ? ???? 2 3 + ?? iii. ?? + ???? 2 4 ? ?? 15 30 + ?? 0 1 iv. ?? 19 40 ? ?? -1 0 + ?? (4 Marks)
c) i) Briefly discuss the practical application of radioactivity in food industry. (4 Marks) ii) Nucleus energy may be both a blessing and a curse. Explain this statement. (4 Marks)
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