Calculate the root mean squared speed for 16g of oxygen gas at 50(deg Celsius) and explain why we use this instead of the average velocity of all the particles.
Root mean squared speed is given by v(rms) = (3kbT/m)^(0.5) = 501.68. Student should show how to calculate the mass of each particle (m = (0.016)/0.5(6.01x10^23)), convert degrees celsius into kelvin and understand that oxygen is a diatomic molecule so there are half as many molecules as with atomic oxygen.The student should show an understanding that the average velocity in three dimensions will often cancel out, giving an average velocity of zero. So to calculate a truly representative average, the average of the squared (and so strictly positive) velocities must be taken and then rooted. This is particularly important in terms of kinetic energy calculations.
JW
Related Physics A Level answers
All answers ▸Can you jump a motorcycle into space?
Why do atoms larger than iron release energy when they undergo fission?
An ultraviolet wave of continuous frequency reflects from a solid surface back in the direction of the transmitter. Assuming no amplitude is lost, describe and explain the behaviour of the particles in the medium between the transmitter and surface.
The Large Hadron Collider (LHC) of circumference 27km uses magnetic fields to accelerate a proton repeatedly in a circular path. Calculate the flux density of a uniform magnetic field required for the proton to travel at a tenth of the speed of light.