The First Law: Vapours and Gases in Closed and Open Systems

We shall begin this programme by looking at problems involving a vapour, usually steam, in closed systems. The system is initially in a known equilibrium state, and as a result of heat and work interactions at the boundary, proceeds to a second equilibrium state. We need to use the equation of the First Law applied to a closed system to solve such a problem. This was given in Frame 11 of Programme 3 as: <math display='block'> <mrow> <mtext>Q&#x00A0;-&#x00A0;W&#x00A0;=&#x00A0;&#x007B;E&#x005F;2&#x007D;&#x00A0;-&#x00A0;&#x007B;E&#x005F;1&#x007D;</mtext> </mrow> </math>]]</EquationSource><EquationSource Format="TEX"><![CDATA[$${\text{Q - W = \{ E\_2\} - \{ E\_1\} }}$$ where the energy term E was shown in Frame 20 of Programme 3 to consist of internal energy, kinetic energy and potential energy. So what would be the First Law equation for problems with steam in closed systems?