Which of these expressions are correct variations of the Combined Gas Law?

A. [tex]T _1 = T _2 \left( \frac{ P _1 V_1}{ P _2 V_2} \right)[/tex]

B. [tex]V _2 = V _1 \left( \frac{ T _2}{ T_1} \right) \left( \frac{ P _1}{ P _2} \right)[/tex]



Answer :

To determine which expressions are correct variations of the Combined Gas Law, let's recall the Combined Gas Law and review each expression step by step.

The Combined Gas Law states:
[tex]\[ \frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2} \][/tex]

We need to analyze each given expression to see if it can be derived correctly from the Combined Gas Law.

### Expression 1:
[tex]\[ T_1 = T_2 \left(\frac{P_1 V_1}{P_2 V_2}\right) \][/tex]

Starting from the Combined Gas Law:
[tex]\[ \frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2} \][/tex]

Isolate [tex]\(T_1\)[/tex]:
[tex]\[ T_1 = T_2 \left(\frac{P_1 V_1}{P_2 V_2}\right) \][/tex]

This expression is derived correctly from the Combined Gas Law.

### Expression 2:
[tex]\[ V_2 = V_1 \left(\frac{T_2}{T_1}\right) \left(\frac{P_1}{P_2}\right) \][/tex]

Starting from the Combined Gas Law:
[tex]\[ \frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2} \][/tex]

Isolate [tex]\(V_2\)[/tex]:
[tex]\[ V_2 = \frac{P_1 V_1 T_2}{P_2 T_1} \][/tex]

Which simplifies to:
[tex]\[ V_2 = V_1 \left(\frac{T_2}{T_1}\right) \left(\frac{P_1}{P_2}\right) \][/tex]

This expression is also derived correctly from the Combined Gas Law.

### Conclusion

Both given expressions:
[tex]\[ T_1 = T_2 \left(\frac{P_1 V_1}{P_2 V_2}\right) \][/tex]
and
[tex]\[ V_2 = V_1 \left(\frac{T_2}{T_1}\right) \left(\frac{P_1}{P_2}\right) \][/tex]

are correct variations of the Combined Gas Law.