Question

chemistry 20
final exam 2025
name: ebtesam
gases

1. a gas is originally at pressure p, volume v and temperature t. the gas is heated

to 7 times the original temperature and reduced to 1/2 of the original pressure.
therefore, the new volume of the gas must be
27v
1/14 v
7/2 v
14 v

Explanation:

Step1: Recall the combined gas law

The combined gas law is given by \(\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}\). Let \(P_1 = P\), \(V_1=V\), \(T_1 = T\), \(P_2=\frac{P}{2}\), \(T_2 = 7T\).

Step2: Substitute values into the formula

Substitute the values into \(\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}\), we get \(\frac{PV}{T}=\frac{\frac{P}{2}\times V_2}{7T}\).

Step3: Solve for \(V_2\)

Cross - multiply: \(PV\times7T=\frac{P}{2}\times V_2\times T\). Cancel out \(P\) and \(T\) (since \(P
eq0\) and \(T
eq0\)). We have \(7V=\frac{V_2}{2}\). Then \(V_2 = 14V\).

Answer:

14V