Verified answer

(15) / (15 + 7) = 0.68

So answer 6.

Moles gas A = pv/rt = 1.5atm x 2L / (zero.0821L-atm/mole-okay x 298K) = zero.123moles fuel A moles fuel B = 0.35atm x 2.5L / (zero.0821L-atm/mole-okay x 298K) = 0.036moles gas B 0.123moles A requires 2.5x moles of B or zero.308moles B, B = limiting reactant 0.036moles B x (2A / 5B) = zero.0144moles A consumed leaving 0.109moles fuel A total moles fuel = moles A + moles A2B5 moles A2B5 = 0.036moles B x (1A2B5 / 5B) = zero.0072moles A2B5 whole moles gas = 0.1162moles prior to the reaction, the pressure within the combined flask is: complete moles = 0.159moles mole fraction A = zero.123 / 0.159 = 0.774 mole fraction B = 0.036 / zero.159 = 0.226 when mixed, partial strain A + partial strain B = total strain (pressureA x mole fractionA + pressureB x mole fractionB) = new stress 1.5atm x zero.774 + zero.35atm x zero.226 = 1.24atm partial stress A + partial pressure A2B5 = complete strain mole fraction A after rxn = 0.109moles / 0.1162moles = 0.938 mole fraction A2B5 after rxn = zero.062 zero.938moles A x 1.24atm + 0.062molels A2B5 x 1.24atm = 1.24atm