Calculate the root mean square velocity of the oxygen gas (O2) molecules at 77 °C. (R =8.314 Kg.m²/S².mol.K). (atomic mass of O-15.999 g/mol)

16.52 x 105 m/s
2.72 x 105 m/s
272.82 x 10 m/s
5.22 x102 m/s

16.52 X 10 to the power of 5 m/s

2.72 X 10 to the power of 5 m/s

5.22 x10 squared m/s

272.82 X 10 m/s

1 answer

(Note: I'm assuming you meant 77 °C and not 77 K, as the latter would result in a negative temperature)

The root mean square velocity, u rms, of a gas is given by the equation:

u rms = √(3RT/M)

where R is the gas constant, T is the temperature in Kelvin, and M is the molar mass of the gas.

First, we need to convert the temperature to Kelvin:

77 °C = (77 + 273.15) K = 350.15 K

Next, we can plug in the values:

u rms = √(3 x 8.314 x 350.15 / 0.032)

where we converted O2's molar mass from grams to kilograms (0.032 kg/mol).

Simplifying this gives:

u rms = 466.4 m/s

Rounding to two significant figures gives:

u rms = 4.7 x 10^2 m/s

Therefore, the closest answer choice is 5.22 x 10^2 m/s.