The thermal decomposition of dimethyl ether

is to be carried out in an isothermal 2.00-liter laboratory reactor at 600°C. The reactor is charged with pure dimethyl ether at a pressure of 350 torr. After about two hours, the reactor pressure is 875 torr.

(a) Has the reaction proceeded to completion at the end of the two-hour period? If not, what percentage of the dimethyl ether has decomposed?

(b) Taking elemental species [C(s), H₂(g), O₂(g)] at 25°C as references, prepare and fill in an inlet–outlet enthalpy table. Use tabulated data for methane, hydrogen, and carbon monoxide, and the following data for dimethyl ether:

(c) Calculate ΔH_r(600°C) and ΔUr(600°C) for the dimethyl ether decomposition reaction.

(d) How much heat (kJ) was transferred to or from the reactor (state which it is) during the two hour period of the reaction?

(e) Suppose the reaction were instead carried out in an expandable reactor at 600°C at a constant pressure of 350 torr, with the same final percentage decomposition of dimethyl ether. Calculate the final volume of the reactor and the required amount of heat transfer. These should both be quick calculations. Explain why the values of Q calculated in Part (d) and in this part are different, even though the initial conditions and extents of reaction are the same.

Transcribed Image Text:

(CH3 ),0(g) → CH4(g) + H2(g) + CO(g)