Reference no: EM132510933

KTT112 Inorganic Chemistry Assignment - University of Science, Malaysia

Q1. (a) Palladium (Pd) is an element with properties similar to those of platinum. It is useful in eliminating harmful emission produce by internal combustion engines. Two students were given identical cylindrical "palladium" bars with the following data:

Mass = 96.03 g; Length = 10.7 cm; Diameter = 9.82 mm; Density = 12.02 gcm^-3

Show the calculations that Student K and S would do if:

(i) Student K was asked to determine whether his bar was made of pure palladium.

(ii) Student S was asked to calculate the grams of ethyl alcohol (d = 0.789 gcm^-3) his bar would displace.

(b) Nitric oxide (NO) is produced in internal combustion engines. When NO comes into contact with air, it is quickly converted into nitrogen dioxide (NO₂), a very poisonous corrosive gas.

(i) Determine the mass of O is that combined with 3.00 g of N in NO and NO₂.

(ii) Describe that NO and NO₂ obey the Law of Multiple Proportion.

(c) PLUTO a drain cleaner is solid sodium hydroxide that contains some aluminium chips. When PLUTO is added to water, the NaOH dissolves rapidly with the evolution of a lot of heat. The Al reduces H₂O in the basic solution to produce [Al(OH)₄]^- ions and H₂ gas, which gives the bubbling action. Write the balanced net ionic and formula unit equations for this reaction.

Q2. (a) A common superconducting oxide is made by heating a mixture of barium carbonate, copper (II) oxide and yttrium (III) oxide, followed by further heating in O₂:

4BaCO₃(s) + 6CuO(s) + Y₂O₃(s) → 2YBa₂Cu₃O_6.5(s) + 4CO₂(g)

2YBa₂Cu₃O_6.5(s) + 1/2O₂(g) → 2YBa₂Cu₃O₇(g)

(i) Identify the limiting reactant when a gram of each of the three reactants are heated.

(ii) Calculate the mass % of each reactant in the remaining solid mixture after the product was removed.

(b) Nitrogen (N), phosphorus (P) and potassium (K) are the main nutrients in plant fertilizer. By industry convention, the numbers on a label refer to the mass % of N, P₂O₅ and K₂O in that order. Calculate the N/P/K ration of a 40/10/10 fertiliser in terms of moles of each element, as x/y/1.0

(c) The following values are the only energy levels of a hypothetical one-electron atom:

E₆ = -2 x 10^-19 J, E₅ = -7 x 10^-19 J

E₄ = -11 x 10^-19 J, E₃ = -15 x 10^-19 J

E₂ = -17 x 10^-19 J, E₁ = -20 x 10^-19 J

(i) If the electron is in the n = 5 level, calculate the highest frequency of radiation that could be emitted.

(ii) Calculate the ionization energy (in kJ mol^-1) of the atom in its ground state.

(iii) If the electron is in the n = 3 level, calculate the shortest wavelength (in nm) of radiation that could be absorbed without causing ionization.

(d) The ionisation energy generally increases across a period. However, there are two exceptions to the otherwise smooth increase in the first ionisation energy across periods. In Periods 2, there are dips at the Group 3A (13) elements, boron and aluminium, and at the Group 6A (16) elements, oxygen and sulfur. Explain this trend using suitable examples.