Avogadro's Number NEET Questions

Physics - Kinetic Theory of Gases

Avogadro's Number MCQ Questions


13.
The perfect gas equation PV = µRT can also be written using Avogadro's number as:
A.
PV = µkBT
B.
PV = NkBT, where N is total number of molecules and kB = R/NA
C.
PV = NA RT
D.
PV = NkBT, where kB = R × NA
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ANSWER :
B. PV = NkBT, where N is total number of molecules and kB = R/NA
14.
The number of molecules per unit volume (number density n) at STP is approximately:
A.
2.7 × 10²⁵ m⁻³
B.
6.02 × 10²³ m⁻³
C.
6.02 × 10²⁵ m⁻³
D.
2.7 × 10²³ m⁻³
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ANSWER :
A. 2.7 × 10²⁵ m⁻³
15.
The number density n at STP is calculated as n = NA / Vmolar. With Vmolar = 22.4 × 10⁻³ m³/mol, the value of n is:
A.
≈ 6.02 × 10²³ m⁻³
B.
≈ 2.69 × 10²⁵ m⁻³ (Loschmidt's number per m³)
C.
≈ 22.4 × 10²⁵ m⁻³
D.
≈ 2.69 × 10²³ m⁻³
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ANSWER :
B. ≈ 2.69 × 10²⁵ m⁻³ (Loschmidt's number per m³)
16.
The molar volume — the volume occupied by 1 mole of any ideal gas at STP (273 K, 1 atm) — is:
A.
11.2 litres
B.
1 litre
C.
22.4 mL
D.
22.4 litres
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ANSWER :
D. 22.4 litres
17.
From Example 12.2 in NCERT, the volume of one water molecule estimated using Avogadro's number (NA = 6 × 10²³) and molar mass of water (18 g) is approximately:
A.
6 × 10⁻³⁰ m³
B.
3 × 10⁻²⁶ m³
C.
18 × 10⁻²³ m³
D.
3 × 10⁻²⁹ m³
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ANSWER :
D. 3 × 10⁻²⁹ m³
18.
The radius of a water molecule estimated from its volume (≈ 3 × 10⁻²⁹ m³) using V = (4/3)πr³ is approximately:
A.
2 × 10⁻⁹ m
B.
2 × 10⁻⁷ m
C.
2 × 10⁻¹⁰ m = 2 Å
D.
2 × 10⁻¹² m
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ANSWER :
C. 2 × 10⁻¹⁰ m = 2 Å