Substituting numerical values R = 8.314 462 618 153 24 J / ( m o l ⋅ ⋅ K ) M a i r = 0.028 964 5 k g / m o l and using the ideal diatomic gas value of γ = 1.4000, we have c a i r ≈ ≈ 331.3 m / s × × 1 + θ θ 273.15 K .