At the boiling point of water,$900 \ J/g$ of heat is exchanged. What is the increase in entropy in $J \ K^{-1} \ mol^{-1}$?

In a reversible expansion,one mole of gas is expanded isothermally at $200 \ K$ till its volume increases $10$ times. Calculate $\Delta S_{total}$ at equilibrium (in $J \ K^{-1}$)?

For the following process $H_2O_{(l)} (1 \ bar, 373.15 \ K) \rightleftharpoons H_2O_{(g)} (1 \ bar, 373.15 \ K)$, identify the correct set of thermodynamic parameters.

Which of the following substances has the highest entropy?

The entropy change involved in the conversion of $1 \, \text{mole}$ of liquid water at $373 \, K$ to vapour at the same temperature will be $[\Delta H_{vap} = 2.257 \, kJ/g]$. (in $, kJ/K$)

For the oxidation of iron:
$4 Fe_{(s)} + 3 O_{2(g)} \rightarrow 2 Fe_2O_{3(s)}$
The entropy change is $-549.4 \ J \ K^{-1} \ mol^{-1}$ at $298 \ K$. Despite the negative entropy change of this reaction,why is the reaction spontaneous?
($\Delta_r H^\Theta$ for this reaction is $-1648 \times 10^3 \ J \ mol^{-1}$)