Classify the following substituents according to whether they are electron donors or electron acceptors relative to hydrogen by the resonance and the inductive mechanisms. a = acceptor d = donor n = no effect 1. Inductive effect d . Resonance effect a . 2. Inductive effect a . Resonance effect d . 3. Inductive effect a . Resonance effect d .

An air standard cycle with variable specific heats is executed in a closed system and is composed of the following four processes. 1-2 isentropic compression 100 kpa and 22°c to 600 kpa 2-3 v=constant heat addition to 1500 k 3-4 isentropic expansion to 100 kpa 4-1 p=constant heat rejection to initial state (a) show the cycle on p-v and t-s s (b) calculate the net work output per unit mass (409 kj/kg) (c) determine the thermal efficiency (47.9%)