Why do experiments need to be repeatable?

7. what temperature is need to just dissolve 50 g of nh4cl in 75 g of water? '

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?

Which statement best describes what happens when molecular compounds melt