Answer : The final temperature of balloon will be, 907 K
Explanation :
Charles' Law : It states that volume of the gas is directly proportional to the temperature of the gas at constant pressure and number of moles.
Mathematically,
[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]
where,
[tex]V_1\text{ and }T_1[/tex] are the initial volume and temperature of the gas.
[tex]V_2\text{ and }T_2[/tex] are the final volume and temperature of the gas.
We are given:
[tex]V_1=2.3L\\T_1=25^oC=(25+273)K=298K\\V_2=7L\\T_2=?[/tex]
Putting values in above equation, we get:
[tex]\frac{2.3L}{298K}=\frac{7L}{T_2}\\\\T_2=906.95K\approx 907K[/tex]
Therefore, the final temperature of balloon will be, 907 K