GIVEN:
VAPOUR DENSITY
= MASS OF CERTAIN GAS (22.4L) AT STP/ MASS OF CERTAIN VOLUME OF H2 GAS (22.4L) AT STP
=Mw/2
=DENSITY OF GAS/DENSITY OF HYDROGEN
1.VAPOUR DENSITY OF A METAL CHLORIDE IS 66. ITS OXIDE CONTAINS 53% METAL. THE ATOMIC MASS OF THE METAL IS
(A) 21
(B)54
(C)27.06
(D)2.086
2.WHICH OF THE FOLLOWING TWO SUBSTANCES HAVE SAME VAPOUR DENSITY?
(A)GLUCOSE,FRUCTOSE
(B)FRUCTOSE, SUCROSE
(C)SUCROSE, GLUCOSE
(D) STARCH, GLUCOSE
Dear Student,
Please find below the solution to the asked query:
Let the mass of the oxide of the metal be 100g
Mass of the metal = 53% = 53g
Mass of Oxygen = 100- 53 = 47g
Number of atoms of O in the molecule = 47/16 = 2.93 or 3
Therefore, the formula of the oxide is M2O3 or valency of metal is 3
Formula of metal chloride = MCl3
Molar mass of MCl3 = 2 Vapour density = 2 66 = 132g
Molar mass of MCl3 = atomic mass of M + 3 atomic mass of Cl
132 = atomic mass of M + 3 35.5
132 = atomic mass of M + 106.5
Atomic mass of M = 132 -106.5 = 25.5 u
The closest answer is option c, 27.06 u
b. Molecules of same molecular mass have the same vapour density. Glucose and fructose have the same molecular mass of 180g/mol and hence the correct option is a.
Hope this information will clear your doubts about vapour density and molecular mass.
If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.
Regards
Please find below the solution to the asked query:
Let the mass of the oxide of the metal be 100g
Mass of the metal = 53% = 53g
Mass of Oxygen = 100- 53 = 47g
Number of atoms of O in the molecule = 47/16 = 2.93 or 3
Therefore, the formula of the oxide is M2O3 or valency of metal is 3
Formula of metal chloride = MCl3
Molar mass of MCl3 = 2 Vapour density = 2 66 = 132g
Molar mass of MCl3 = atomic mass of M + 3 atomic mass of Cl
132 = atomic mass of M + 3 35.5
132 = atomic mass of M + 106.5
Atomic mass of M = 132 -106.5 = 25.5 u
The closest answer is option c, 27.06 u
b. Molecules of same molecular mass have the same vapour density. Glucose and fructose have the same molecular mass of 180g/mol and hence the correct option is a.
Hope this information will clear your doubts about vapour density and molecular mass.
If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.
Regards