Use your trendline equation to determine the gas pressure at 200 K and 400 K. (notice the temperature units) How many times greater is the pressure at 400 K in comparison to 200 K? Is this what you'd expect? Why?

The pressure will be twice the initial pressure

Explanation:

Gay-Lussac's law states that the pressure of a gas is directely proportional to absolute temperature under constant volume. That is because vibrations of a gas increase when temperature increases, increasing the pressure of the gas.

That means if the temperature of a gas is doubled, the pressure will be twice the initial pressure.