Q is the totle heat of ideal gas
m is the mass of ideal gas
u is the sound speed of ideal gas

You may understand this equation on experiment details .

There is no such thing as "total heat". That being said, the equation you are looking for is &gamma; R T = M c<SUP>2</SUP>. In this equation, &gamma; is a number called the adiabatic constant which is defined as the ratio of the heat capacity at constant pressure to the heat capacity at constant volume. For a monatomic ideal gas, the constant is 5/3, and for real air it is something like 1.4. R is the gas constant, T is the temperature of the gas, M is the mass of the gas particles, and c is the speed of sound in the gas.

See here for details: http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe3.html#c1

P.S. Unfortunately we have no LaTeX support here.

I am from China and glad to meet you . Thanks for your replying . On experiment details , which is better Q = muu or γ R T = M c 2 ? γ R T = M c 2 is based on Laplace theory . Q = muu , such idea is directly from E = mcc . Resnick has ever thought that the sound speed is less than the energy speed of gas , then how to calculate the energy speed of ideal gas ?