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Explain, giving three reasons, why tropics show greatest levels of species diversity.
Concept: Patterns of Biodiversity
An element has atomic mass 93 g mol−1 and density 11.5 g cm–3. If the edge length of its unit cell is 300 pm, identify the type of unit cell. (NA = 6.023 × 1023 mol−1)
Concept: Number of Atoms in a Unit Cell
Calculate the number of unit cells in 8.1 g of aluminium if it crystallizes in a f.c.c. structure. (Atomic mass of Al = 27 g mol–1)
Concept: Number of Atoms in a Unit Cell
Give reasons:Ferrimagnetic substances show better magnetism than antiferromagnetic substances.
Concept: Properties of Solids: Magnetic Properties
Calculate the e.m.f. of the following cell at 298 K:
Fe(s) | Fe2+ (0.001 M) | | H+ (0.01 M) | H2(g) (1 bar) | Pt(s)
Given that \[\ce{E^0_{cell}}\] = 0.44 V
[log 2 = 0.3010, log 3 = 0.4771, log 10 = 1]
Concept: Nernst Equation - Introduction
Calculate the degree of dissociation (α) of acetic acid if its molar conductivity (Λm) is 39.05 S cm2 mol−1.
(Given \[\ce{\lambda^{\circ}_{(H^+)}}\] = 349.6 S cm2 mol−1 and \[\ce{\lambda^{\circ}_{(CH_3COO^-)}}\] = 40.95 S cm2 mol−1)
Concept: Conductance of Electrolytic Solutions >> Variation of Conductivity and Molar Conductivity with Concentration
Account for the following:
E° value for the Mn3+/Mn2+ couple is highly positive (+1.57 V) as compare to Cr3+/Cr2+.
Concept: Galvanic Cells - Measurement of Electrode Potential
Which of the following cell was used in the Apollo space programme?
Concept: Fuel Cells
For a reaction A + B ⟶ P, the rate is given by
Rate = k [A] [B]2
How is the rate of reaction affected if the concentration of B is doubled?
Concept: Factors Influencing Rate of a Reaction
For a reaction A + B ⟶ P, the rate is given by
Rate = k [A] [B]2
What is the overall order of reaction if A is present in large excess?
Concept: Factors Influencing Rate of a Reaction
For a chemical reaction R → P, the variation in the concentration (R) vs. time (t) plot is given as:
(i) Predict the order of the reaction.
(ii) What is the slope of the curve?
(iii) Write the unit of rate constant for this reaction.
Concept: Factors Influencing Rate of a Reaction
A first-order reaction is 50% complete in 30 minutes at 300 K and in 10 minutes at 320 K. Calculate activation energy (Ea) for the reaction. [R = 8.314 J K−1 mol−1]
[Given: log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021]
Concept: Temperature Dependence of the Rate of a Reaction
Account for the following:
Mn shows the highest oxidation state of +7 with oxygen but with fluorine, it shows oxidation state of +4.
Concept: General Properties of the Transition Elements (d-block)
Account for the following:
Cu+2 salts are coloured, while Zn2+ salts are white.
Concept: General Properties of the Transition Elements (d-block)
Give a reason for the following:
Actinoids show irregularities in their electronic configurations.
Concept: F-block Elements >> The Actinoids
Give an example and suggest a reason for the following feature of the transition metal chemistry:
The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Account for the following:
Mn2+ is more stable than Fe2+ towards oxidation to +3 state.
Concept: Electronic Configurations of the d-block Elements
Why \[\ce{HCl}\] should not be used for potassium permanganate titrations?
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Account for the following:
Transition metals form alloys.
Concept: General Properties of the Transition Elements (d-block)
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
Concept: General Properties of the Transition Elements (d-block)
