The speed of sound in a gas is determined by its temperature and molar mass, not its density.

$$v = 331 \sqrt{\frac{T}{M}}$$

where:

\(v\) = speed of sound (m/s)

\(T\) = temperature (K)

\(M\) = molar mass (g/mol)

As the temperature increases, the speed of sound also increases. As the molar mass increases, the speed of sound decreases. Density is not a factor in the calculation of the speed of sound.