Đáp án:
\(\begin{array}{l}
19.A\\
{p_1}{V_1} = {p_2}{V_2}\\
\Rightarrow \dfrac{{{p_1}}}{{{p_2}}} = \dfrac{{{V_2}}}{{{V_1}}}(1)\\
m = {D_1}{V_1} = {D_2}{V_2}\\
\Rightarrow \dfrac{{{V_2}}}{{{V_1}}} = \dfrac{{{D_1}}}{{{D_2}}}(2)\\
(1),(2) \Rightarrow \dfrac{{{p_1}}}{{{p_2}}} = \dfrac{{{V_2}}}{{{V_1}}} = \dfrac{{{D_1}}}{{{D_2}}}\\
20.A\\
\dfrac{{{V_1}}}{{{T_1}}} = \dfrac{{{V_2}}}{{{T_2}}} \Rightarrow \dfrac{{{V_2}}}{{{V_1}}} = \dfrac{{{T_2}}}{{{T_1}}}(1)\\
\dfrac{{{V_2}}}{{{V_1}}} = \dfrac{{{D_1}}}{{{D_2}}}(2)\\
(1).(2) \Rightarrow \dfrac{{{D_1}}}{{{D_2}}} = \dfrac{{{V_2}}}{{{V_1}}} = \dfrac{{{T_2}}}{{{T_1}}}\\
22.B\\
\dfrac{{{D_1}}}{{{D_2}}} = \dfrac{{{V_2}}}{{{V_1}}} = \dfrac{{{T_2}}}{{{T_1}}} \Rightarrow D \sim \dfrac{1}{T}\\
23.B\\
\dfrac{{{p_1}}}{{{p_2}}} = \dfrac{{{V_2}}}{{{V_1}}} = \dfrac{{{D_1}}}{{{D_2}}} \Rightarrow D \sim \dfrac{1}{T}\\
24.\\
{p_1}{V_1} = {p_2}{V_2} \Rightarrow 0,{5.10^3}.{V_1} = {4.2.10^3}\\
\Rightarrow {V_1} = 16l
\end{array}\)
