What type of reaction is iron+ sulfur

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?

Water undergoes a large change in density at 0 ∘ c as it freezes to form ice. calculate the percent change in density that occurs when liquid water freezes to ice at 0 ∘ c given that

What is the work done by the electric force to move a 1 c charge from a to b?