QUESTION $1$

$1\mathrm{.}1$ Calculate the change in entropy when $100\mathrm{.}0g$ of water at $80\mathrm{.}0C$ is poured into $100g$ of water at $10\mathrm{.}0C$ in an insulated vessel given that

$(10)$

$C_{p,m}=75\mathrm{.}5J{K}^{-1}mo{l}^{-1}.$

$1\mathrm{.}2$ A sample of carbon dioxide that initially occupies $20\mathrm{.}0d{m}^3$ at $250K$ and $1\mathrm{.}00$atm is compressed isothermally. Into what volume must the gas be compressed to reduce its entropy by $10\mathrm{.}0J{K}^{-1}?$

$1\mathrm{.}3$ Phase Diagram of Sulphur:

$1\mathrm{.}3\mathrm{.}1$ Draw and label the phase diagram of sulphur.

$1\mathrm{.}3\mathrm{.}2$ From the phase diagram in $1\mathrm{.}3\mathrm{.}1,$ explain three bivariant conditions.

$(7)$

$1\mathrm{.}4$ Reduced Phase rule:

$1\mathrm{.}4\mathrm{.}1$ What is the formula for reduced phase rule?

$1\mathrm{.}4\mathrm{.}2$ Under what condition$($s$)$ is$/$are the reduced phase rule applied?

$1\mathrm{.}5$ Answer the following questions based on Figure $1$:

Figure $1$: Phase diagram of a silver$-$lead system

$1\mathrm{.}5\mathrm{.}1$ At what point is the melting point of the silver$-$lead composite the lowest?

$1\mathrm{.}5\mathrm{.}2$ What is the name given the point identified in $Q1\mathrm{.}5\mathrm{.}1?$

$1\mathrm{.}5\mathrm{.}3$ Explain two practical applications of the point identified

$1\mathrm{.}5\mathrm{.}2.$

$1\mathrm{.}5\mathrm{.}4$ What is the degree of freedom for curve BC$?$

$[50]$