Final answer:
Adjusting the gas valve on a Bunsen burner does indeed change the volume of gas flow, increasing the size of the flame.
Step-by-step explanation:
The statement is true. Adjusting the gas valve on a Bunsen burner does change the volume of gas flow. When more gas is allowed to enter the burner, the volume of gas flow increases, resulting in a larger flame. This is because the volume of a gas is directly proportional to the amount of gas present, according to Avogadro's law.
For example, if you open the gas valve more, more gas molecules will enter the burner, leading to an increase in the volume of gas and a larger flame. Conversely, if you close the gas valve, less gas will enter the burner, decreasing the volume of gas and resulting in a smaller flame.