- #1
Luke Attigan
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Homework Statement
At T1 the root mean square speed (rms) of compound P is 485.2 m s-1 and at T2 the rms speed is 504.1 m s-1. Using this data and the fact that T2 – T1 = 24.0 °C, determine the molar mass of P in g mol-1.
Homework Equations
- From problem statement you have: (3·R·T1/M)1/2 = 485.2 and (3·R·T2/M)1/2 = 504.1
- You also have that T2 - T1 = 24.0 °C ≡ 24.0 K
- Together, (1) and (2) form a system of 3 algebraic equations with 3 unknowns (T1, T2 and M) that can be easily solved
- Solve the equation system by first calculating T1 and T2
- Once T1 and T2 are known use one of the expression in (1) to calculate M
The Attempt at a Solution
I have the 3 equations:485.2 = (3RT1/M)^0.5
504.1 = (3RT2/M)^0.5
T2 – T1 = 24 K
I have squared these equations, (rms)^2 = 3RT/M, in order to eliminate the square root to make the equation as simple as possible, however that is all I have so far and do not understand how to calculate M with two three unknown variables T1, T2 and M. Could you please give me some assistance?