### Class XI

Estimate the average thermal energy of a helium atom at the temperature on the surface of the Sun (6000 K)
1. 1.24 ×× 10−1910−19 J
2. 1.28 ×× 10−1910−19 J
3. 1.28 ×× 10−1910−19 J
4. 1.35 ×× 10−1910−19 J
An oxygen cylinder of volume 30 liters has an initial gauge pressure of 15 atm and a temperature of 27 ∘∘C. After some oxygen is withdrawn from the cylinder, the gauge pressure drops to 11 atm and its temperature drops to 17 ∘∘C. Estimate the mass of oxygen taken out of the cylinder (R = 8.31 J mol−1mol−1 K−1K−1, molecular mass of O2O2 = 32 u).
1. 0.13 kg
2. 0.12 kg
3. 0.10 kg
4. 0.16 kg
How many atoms of helium gas fill a balloon of diameter 30.0 cm at 20.0∘∘C and 1.00 atm?
1. 3.73 ×× 10231023 atoms
2. 3.53 ×× 10231023 atoms
3. 3.33 ×× 10231023 atoms
4. 3.13 ×× 10231023 atoms
Molar volume is the volume occupied by 1 mol of any (ideal) gas at standard temperature and pressure (STP : 1 atmospheric pressure, 0 ∘∘C). The value of Molar volume is
1. 22.4 liters
2. 23.7 liters
3. 20.4 liters
4. 24.4 liters
A spherical balloon with a volume of 4 000 cm3cm3 contains helium at an (inside) pressure of 1.20 ×× 105105 Pa. How many moles of helium are in the balloon if each helium atom has an average kinetic energy of 3.60 ×× 10−2210−22 J?
1. 3.42 mol
2. 3.82 mol
3. 3.12 mol
4. 3.32 mol
0
0

### Get Started!

we provide the best
services to our students

Views

Rs 1,999  Annual
Plan

TOP