Question

Un gaz ideal ce ocupa volumul V1=20L se afla sub presiunea p1=10^5 Pa la temperatura t1=17C. Care va fi presiunea gazului, daca aceeasi masa de gaz la temperatura t2=100C va ocupa volumul V2=10L?

Answer 1

 

$\displaystyle\bf\\Folosim~formula:~~~~~\frac{PV}{T}=constant~(pentru~aceeasi~masa~de~gaz.)\\\\unde:\\P=presiunea~absoluta~(N/m^2~sau~Pa)~......~1~Pa = 1~N/m^2\\V=volumul\\T=temperatura~absoluta~(^oK)\\\\V_1=20~L\\P_1=10^5~Pa\\t_1=17^oC\\T1=(17+273)^oK=290^oK\\-----\\V_2=10~L\\t_2=100^oC\\T_2=(100+273)^oK=373^oK\\P_2=?$

.

$\displaystyle\bf\\\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}\\\\\\P_2=\frac{P_1V_1}{T_1}:\frac{V_2}{T_2}=\frac{P_1V_1}{T_1}\times\frac{T_2}{V_2}=\frac{P_1V_1T_2}{T_1V_2}=P_1\times\frac{V_1}{V_2}\times\frac{T_2}{T_1}=  \\\\\\=10^5Pa\times\frac{20L}{10L}\times\frac{373^oK}{290^oK}=10^5Pa\times2\times1,286=\boxed{\bf2,572\cdot10^5~Pa}$