If I compress a gas, is the work positive or negative? Will it get cold or hot (assume it is thermally insulated)? If I compress a gas under isothermal conditions, how is it that the temperature is constant? If there is a heat exchange, is it positive or negative?

b) How is reversible heating different from irreversible heating? 

c) Why can't adiabatic irreversible transitions have DS < 0 J K-1 (i.e. negative system entropy changes)? 

d) Does it help a reaction to go forward if the reactant molecule creates more gas molecule products (for example, A -> 2B)? Why or why not? 

e) Why is the heat capacity at constant pressure higher than the heat capacity at constant volume