CBSE Class 11 Mole Concept Percentage Composition Worksheet

CALCULATION & LAWS OF CHEMICAL COMBINATION

Q.1 Calculate the followingquantities :

(a) Mass, in grams, of 0.1mol of sucrose (C₁₂H₂₂O₁₁)

(b) Moles of Zn(NO₃)₂ in 142.05 g of this substance

(c) Number of molecules of HCOOH in 10^–6mol.

(d) Number of N-atom in 0.2mol of N₂H₄.

(e) Number of O-atom in 2 × 10^–3 molAl(NO₃)₃.

(f) Number ofmoles of NH4Cl in 10⁷ g of this substance.

(g) Mass, in grams of 2 × 10^–3mol of CdS

(h) Molarmass of Cholesterol if 0.00105mol has amass of 0.525 g

(i) Mass, in grams, of 3 × 10²¹molecules ofAspirin, C₉H₈O₄

(j) Molarmass of an element ifmass of 1 atom is 12 × 10^–24 g.

(k) Number of SO₄^2– ions in 19.6 g Cr₂(SO₄)₃

(l) Number of Ca²⁺ ions in 6.2 g Ca₃(PO₄)₂

(m) Number ofmoles of 11.2 LCO₂ at NTP

(n) Number ofmoles of 2LCO₂ at 16.42 atmpressure and 127°C.

(o) Molarmass of gas at 1atmand 27°C having density 1.2 × 10^–3 g/ml

(p) Number ofmoles of 45.4 LO₂ at STP

Q.2 Nitric acid is composed of HNO₃ molecules. If a sampleweighing 6.3 g HNO₃ then calculate
(a) Howmany nitrogen atoms are in this sample?
(b) Howmany oxygen atoms are in 2.52 gmof nitric acid.

Q.3 Complete the following table for an ideal gas
           P                                  V               n                 Temperature
(i) 16.628 × 10³ Pa              15 L           ______           27°C
(ii) __________                    42 L          0.42mol          200K
(iii) 304 torr                         ______      4 × 10^–2         327°C
(iv) 380mmHg                    ______      0.5mol            300K

Q.4 The relative density of a mixture of CO₂ (g) & H₂O (g) w.r.t. gaseous hydrogen atoms is 30. Then Calculatemol percentage of CO₂

Q.5 Ethanol,C₂H5OH, is the substance commonlycalled alcohol.The densityof liquid alcohol is 0.7893 g/ml at 293K. If 1.2mole of ethanol are needed for a particular experiment,what volume of ethanol
should bemeasured out?

Q.6 Asample of claycontains 50%silica and 10%water.The sample is partiallydried bywhich it loses 8 gm water. If the percentage of silica in the partially dried clay is 52, calculate the percentage ofwater in the partiallydried clay?

Q.7 Agaseous mixture contains CO₂ (g) and N₂O(g) in a 2 : 5 ratio bymass. Find the ratio of the number of molecules of CO₂ (g) and N₂O(g)

Q.8 Find the number of neutrons in 0.45 gwater, assuming that all the hydrogen atoms are H₁ atoms and all the oxygen atoms are O16 atoms