A50.0 ml sample if 0.0500 m ca(oh)2 is added to 10.0 ml of 0.0200m hno3. how many miles of excess acid or base are present?

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?