Answer:
Lighting the lighter after step #2 will either cause an increase in volume due to temperature rise, as per Charles's Law, or an increase in pressure, as per Gay-Lussac's Law, depending on whether the container is flexible or has a fixed volume.
Step-by-step explanation:
Attempting to light the lighter after step #2 will affect the calculations related to temperature and volume or pressure and volume, depending on the context of the previous steps. In the general concept of gases, if the temperature of the gas increases due to lighting the lighter, it will cause the volume to increase, assuming the gas is in a flexible container like a balloon. This is outlined by Charles's Law which states that the volume of a gas is directly proportional to its temperature when the pressure is held constant.
On the other hand, if the experiment setup is such that the container's volume cannot change, then the increase in temperature would cause an increase in pressure inside the container according to Gay-Lussac's Law where the pressure of a gas is directly proportional to its temperature at constant volume.