$3.$ Use equation $2\mathrm{.}40$ to find the effects on the cell voltage of a Solid Oxide Fuel Cell, operating at $800$ o C$,$ of $(1)$ changing from pure hydrogen to $50\%$ hydrogen, $50\%$ carbon dioxide, $(2)$ changing the system pressure from $1$ to $3$ bar, and $(3)$ Changing the changing the cathode gas from air to pure oxygen? Reference book: FUEL CELL SYSTEMS by ANDREW L$.$ DICKS and DAVID A$.$ J$.$ RAND