a.
$p_1=2.10^5Pa$ $p_2=4.10^5Pa$ $p_3=?$
$v_1=5 lít$ $v_2=v_1$ $v_3=10 lít$
$T_1=303°K$ $T_2=?$ $T_3=T_2$
b.
(1)->(2): đẳng tích
$\dfrac{p_1}{T_1}=\dfrac{p_2}{T_2}$
$=>\dfrac{2.10^5}{303}=\dfrac{4.10^5}{T_2}$
$=>T_2=606°K$
(2)->(3): đẳng nhiệt
$p_2v_2=p_3v_3$
$=>4.10^5.5=p_3.10$
$=>p_3=2.10^5 Pa$