Which of these scenarios involve a reaction that is at equilibrium? a). the reaction is producing more products than reactants b). the reaction is producing more reactants than products c). the amount of products and reactants is changing d). the amount of products and reactants is constant

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?