wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

(a) The volumes of gases A, B, C and D, are in the ratio, 1 : 2 : 2 : 4 under the same conditions of temperature and pressure.
(i) Which sample of gas contains the maximum number of molecules?
(ii) If the temperature and the pressure of gas A are kept constant then what will happen to the volume of A when the number of molecules is doubled?
(iii) If this ratio of gas volumes refer to the reactants and products of a reaction, which gas law is being observed?
(iv) If the volume of A is actually 5.6 dm3 at STP, calculate the number of molecules in the actual volume of D at STP.
(Avogadro's number is 6 × 1023).
(v) Using your answer from (iv), state the mass of D if the gas is dinitrogen oxide (N2O).
(N = 14; O = 16)
(b) Calculate the percentage of nitrogen in aluminium nitride. (Al = 27, N = 14)

Open in App
Solution

(a)
(i) Ratio of volume of gas D is the highest. Hence, according to the Avogadro's law, gas D has maximum number of molecules.

(ii) According to the ideal gas equation,
PV = nRT
At constant pressure and temperature, volume of gas is directly proportional to the number of moles or number of molecules of the gas. Hence, if number of molecules of A is doubled, its volume will also be doubled.

(iii) Gay-Lussac's law is being observed in the given ratio. This law states that reacting volumes of the gases bears a simple ratio to another and also to the volumes of the gaseous products, under conditions of same temperature and pressure.

(iv) Volume of gas D is four times the volume of gas A. Hence, if volume of gas A is 5.6 dm3, then volume of gas D is 22.4 dm3.
Number of molecules of gas D = Number of moles × Avogadro's Number
= Volume of gas DMolar volume of gas D at STP×6.022×1023
= 22.422.4×6.022×1023
= 6.022 ×1023
(v) Mass of one mole of gas D or (N2O) = Number of moles × Molecular mass of N2O
= 1 × [(14)2 + 16] = 44 g

(b) Molar mass of aluminium nitride (AlN) = 27 g + 14 g = 41 g
Mass of nitrogen in aluminium nitride = 14 g
Percentage of N = Mass of N in compoundMolecular mass of AlN×100=1441×100=34.1%


flag
Suggest Corrections
thumbs-up
2
similar_icon
Similar questions
View More
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Mole concept and Avogadro's Number
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon