Two samples of liquid water

CHEMISTRY · Single correct · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

Two samples of liquid water, each of mass

0.50\,\text{kg}

, are at

80\,^{\circ}\text{C}

and

20\,^{\circ}\text{C}

respectively. They are mixed adiabatically in an isolated vessel. (Take the specific heat of water as

4.2\,\text{kJ kg}^{-1}\,\text{K}^{-1}

.) The entropy change of the universe is closest to (a)

0\,\text{J K}^{-1}

(b)

-17\,\text{J K}^{-1}

(c)

+17\,\text{J K}^{-1}

(d)

+37\,\text{J K}^{-1}