Two aluminum blocks

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Thermodynamics · Thermodynamics

Problem

Two

1.0\,\text{kg}

aluminum blocks, each with specific heat capacity

c=900\,\text{J}\,\text{kg}^{-1}\,\text{K}^{-1}

, are placed in thermal contact inside an insulated container. Block A is initially at

400\,\text{K}

and block B at

300\,\text{K}

. They eventually reach the common temperature

350\,\text{K}

. Which of the following is closest to the total change in entropy

\Delta S_{\text{total}}

of the two-block system? (a)

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

(b)

+9\,\text{J}\,\text{K}^{-1}

(c)

+18\,\text{J}\,\text{K}^{-1}

(d)

-18\,\text{J}\,\text{K}^{-1}