Ex 6 - The dissociation vapour pressure of NH4Cl at 427C is 608kPa but at 459C it has risen to 1115kPa. Calculate a) the equilibrium constant b) the standard reaction Gibbs energy c) the standard enthalpy d) the standard entropy of dissociation all at 427C. Assume that the vapour behaves as a perfect gas and that H0 and S are independent of temperature in the range given. NH4Cl(s)NH3(g)+HCl(g) Exercise 7. Define function f(x)=x45x2+4 in the Symbolic Toolbox. Substitute x with t