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An element crystallizes in a f.c.c. lattice with a cell edge of 250 pm. Calculate the density if 300 g of this element contains 2 × 1024 atoms.
Concept: Calculations Involving Unit Cell Dimensions
Calculate the freezing point of solution when 1.9 g of MgCl2 (M = 95 g mol−1) was dissolved in 50 g of water, assuming MgCl2 undergoes complete ionization.
(Kf for water = 1.86 K kg mol−1)
Concept: Colligative Properties and Determination of Molar Mass >> Depression of Freezing Point
Out of 1 M glucose and 2 M glucose, which one has a higher boiling point and why?
Concept: Colligative Properties and Determination of Molar Mass >> Elevation of Boiling Point
What happens when the external pressure applied becomes more than the osmotic pressure of solution?
Concept: Colligative Properties and Determination of Molar Mass >> Osmosis and Osmotic Pressure
When 2.56 g of sulphur was dissolved in 100 g of CS2, the freezing point lowered by 0.383 K. Calculate the formula of sulphur (Sx).
(Kf for CS2 = 3.83 K kg mol−1, Atomic mass of sulphur = 32 g mol−1]
Concept: Colligative Properties and Determination of Molar Mass >> Depression of Freezing Point
Blood cells are isotonic with 0.9% sodium chloride solution. What happens if we place blood cells in a solution containing
(i) 1.2% sodium chloride solution?
(ii) 0.4% sodium chloride solution?
Concept: Colligative Properties and Determination of Molar Mass >> Osmosis and Osmotic Pressure
What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 1/3rd of tetrahedral voids?
Concept: Crystal Lattices and Unit Cells
What is meant by positive deviations from Raoult's law? Give an example. What is the sign of ∆mixH for positive deviation?
Concept: Vapour Pressure of Liquid >> Vapour Pressure of Liquid- Liquid Solutions
3.9 g of benzoic acid dissolved in 49 g of benzene shows a depression in freezing point of 1.62 K. Calculate the van't Hoff factor and predict the nature of solute (associated or dissociated).
(Given : Molar mass of benzoic acid = 122 g mol−1, Kf for benzene = 4.9 K kg mol−1)
Concept: Abnormal Molar Masses
An element with molar mass 27 g mol−1 forms a cubic unit cell with edge length 4.05 ✕ 10−8 cm. If its density is 2.7 g cm−3, what is the nature of the cubic unit cell?
Concept: Number of Atoms in a Unit Cell
Define the following term
Schottky defect
Concept: Imperfections in Solids - Introduction
An element with density 2.8 g cm–3 forms a f.c.c. unit cell with edge length 4 x 10–8 cm. Calculate the molar mass of the element.
(Given : NA = 6.022 x 1023 mol –1)
Concept: Calculations Involving Unit Cell Dimensions
Define the following terms : Molarity
Concept: Solubility >> Solubility of a Solid in a Liquid
Define the following term:
Molal elevation constant (Kb)
Concept: Colligative Properties and Determination of Molar Mass >> Elevation of Boiling Point
A solution of glucose (molar mass = 180 g mol–1) in water is labelled as 10% (by mass). What would be the molality and molarity of the solution ? (Density of solution = 1.2 g mL–1)
Concept: Colligative Properties and Determination of Molar Mass
Write any two differences between amorphous solids and crystalline solids
Concept: Amorphous and Crystalline Solids
Give reasons : In stoichiometric defects, NaCl exhibits Schottky defect and not Frenkel defect.
Concept: Imperfections in Solids >> Types of Point Defects - Stoichiometric Defects
Give reasons : Silicon on doping with Phosphorous forms n-type semiconductor.
Concept: Properties of Solids: Electrical Properties >> Applications of n-type and p-type Semiconductors
An element with density 11.2 g cm–3 forms a f.c.c. lattice with edge length of 4 × 10–8 cm.
Calculate the atomic mass of the element.
(Given : NA = 6.022 × 1023 mol–1)
Concept: Calculations Involving Unit Cell Dimensions
