10.0 mL of a 0.251 M NaCl solution are diluted to a total new volume of 35.0 mL. What is the new molarity of the solution?

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?