Given the entropy of $H_2$ and $HBr$ are $130.6 \, JK^{-1}$ and $198.5 \, JK^{-1}$ respectively,calculate the entropy of $Br_{2(g)}$ in the reaction $H_{2(g)} + Br_{2(g)} \rightarrow 2HBr_{(g)}$ where $\Delta S^{o} = 20.1 \, JK^{-1}$.

In which state does matter have the highest entropy?

The enthalpy of vapourization of a liquid is $30 \ kJ \ mol^{-1}$ and entropy of vapourization is $75 \ J \ mol^{-1} \ K^{-1}$. The boiling point of the liquid at $1 \ atm$ is.......$K$

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 $-1648 \times 10^3 \ J \ mol^{-1}$)

$A$ reversible adiabatic process is one in which:

For which of the following processes is $\Delta S$ negative?