As the volume is decreased and the pressure is increased to the given value, the temperature of the gas increases to 81.67°C.
Given the data in the question;
Combined gas law brings together both Boyle's Law, Charles's Law, and Gay-Lussac's Law. It states that "the ratio of the product of volume and pressure and the absolute temperature of a gas is equal to a constant.
It is expressed as;
[tex]\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}[/tex]
We substitute our given values into the expression above to determine the new temperature.
[tex]\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}\\\\P_1V_1T_2 = P_2V_2T_1\\\\T_2 = \frac{P_2V_2T_1}{P_1V_1}\\T_2 = \frac{1.0atm\ *\ 0.4L\ *\ 350.15K}{0.789474atm\ *\ 0.5L} \\\\T_2 = \frac{140.06LatmK}{0.394737Latm}\\ \\T_2 = 354.82K\\\\T_2 = 81.67^oC[/tex]
Therefore, as the volume is decreased and the pressure is increased to the given value, the temperature of the gas increases to 81.67°C.
Learn more about the combined gas law here: brainly.com/question/25944795