describe how you would prepare 0.5M sodium carbonate solution using a 250cm3 volumetric flask and use it to determine the concentration of dilute hydrochloric acid. Your description should go as far as data collection​

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?