流れる気体の問題

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\usepackage{tetsuchem}
\pagestyle{fancy}

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\カスタム用紙サイズ{縦=5cm,横=9.75cm}

\begin{document}

\begin{tikzpicture}
\fill[draw,black!35!white] (0,0) -- (3,0) -- (3,1) -- (0,1) --cycle;
\draw (0,0) -- (3,0) -- (3,3) -- (0,3) --cycle;
\draw (0.5,0.75) -- (0.5,3.5) -- (-0.75,3.5);
\draw (0.75,0.75) -- (0.75,3.75) -- (-0.75,3.75);
\fill[white] (0.507,0.75) -- (0.743,0.75) -- (0.743,3.743) -- (0.507,3.743) --cycle;
\fill[white] (0.65,0.5) circle (2.5pt);
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\draw (2.25,2.5) -- (2.25,3.75) -- (3.5,3.75) -- (3.5,4.25) -- (5.5,4.25);
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\fill[draw] (5.25,4.25) -- (5,4.25) -- (5,3) -- (5.25,3) --cycle;
\node[anchor=south east] at (-0.75,3.75) {$P_0\〔\Pa〕$の空気};
\node[left] at (-0.75,3.625) {$V_0\〔\L〕$\→};
\node[above] at (-0.125,3.75) {入口A};
\node[below] at (1.5,0) {容器B};
\node at (1.5,0.5) {水};
\node[above] at (2.75,3.75) {出口C};
\node[above] at (4.25,4.25) {容器D};
\node[right] at (5.25,3.625) {\← $P_0\〔\Pa〕$};
\end{tikzpicture}

\end{document}