The gas phase decomposition of dimethyl ether at 500 °C
CH3OCH3(g) —> CH4(g) + H2(g) + CO(g)
is first order in CH3OCH3 with a rate constant of 4.00×10-4s-1.
If the initial concentration of CH3OCH3 is 0.129 M, the concentration of CH3OCH3 will be ___________ M after 3155 s have passed.