Class 12th Chemistry 2017 Set2 Delhi Board Paper Solution

Question 26

Calculate the number of unit cells in 8.1 g of aluminium if it crystallises in a f.c.c. structure. (Atomic mass of Al = 27 g mol -1 )

Answer

27 g of Aluminium have 6.02 x 1023 atoms of Al

8.1g of Aluminium have 6.02 x 1023 x 8.1 / 27

= 12.06 x 1022 atoms of Aluminium

Now in FCC structure:

1 unit cell has 4 Aluminium atoms i.e.,

12.06 x 1022 atoms have 1/4 x 12.06 x 1022 unit cells

= 3.05x 1022 unit cells

Previous Question Next Question

Popular Questions of Class 12th chemistry

Q:-
Give simple chemical tests to distinguish between the following pairs of compounds.

(i) Propanal and Propanone

(ii) Acetophenone and Benzophenone

(iii) Phenol and Benzoic acid

(iv) Benzoic acid and Ethyl benzoate

(v) Pentan-2-one and Pentan-3-one

(vi) Benzaldehyde and Acetophenone

(vii) Ethanal and Propanal
Q:-
How the following conversions can be carried out?

(i) Propene to propan-1-ol

(ii) Ethanol to but-1-yne

(iii) 1-Bromopropane to 2-bromopropane

(iv) Toluene to benzyl alcohol

(v) Benzene to 4-bromonitrobenzene

(vi) Benzyl alcohol to 2-phenylethanoic acid

(vii) Ethanol to propanenitrile

(viii) Aniline to chlorobenzene

(ix) 2-Chlorobutane to 3, 4-dimethylhexane

(x) 2-Methyl-1-propene to 2-chloro-2-methylpropane

(xi) Ethyl chloride to propanoic acid

(xii) But-1-ene to n-butyliodide

(xiii) 2-Chloropropane to 1-propanol

(xiv) Isopropyl alcohol to iodoform

(xv) Chlorobenzene to p-nitrophenol

(xvi) 2-Bromopropane to 1-bromopropane

(xvii) Chloroethane to butane

(xviii) Benzene to diphenyl

(xix) tert-Butyl bromide to isobutyl bromide

(xx) Aniline to phenylisocyanide
Q:-
A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K.
Q:-
A solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL^-1, then what shall be the molarity of the solution?
Q:-
Henry's law constant for CO₂ in water is 1.67 x 10⁸Pa at 298 K. Calculate the quantity of CO₂in 500 mL of soda water when packed under 2.5 atm CO₂pressure at 298 K.
Q:-
Calculate the mass of a non-volatile solute (molar mass 40 g mol^-1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.
Q:-
The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K. Find out the composition of the liquid mixture if total vapour pressure is 600 mm Hg. Also find the composition of the vapour phase.
Q:-
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
Q:-
How many mL of 0.1 M HCl are required to react completely with 1 g mixture of Na₂CO₃ and NaHCO₃ containing equimolar amounts of both?
Q:-
If NaCl is doped with 10^-3mol % of SrCl₂, what is the concentration of cation vacancies?

Class 12th Chemistry 2017 Set2 Delhi Board Paper Solution

Calculate the number of unit cells in 8.1 g of aluminium if it crystallises in a f.c.c. structure. (Atomic mass of Al = 27 g mol -1 )

Popular Questions of Class 12th chemistry

Recently Viewed Questions of Class 12th chemistry

NCERT Solutions

Quick Links

Resources

Support