What is the formula for calcium hydroxide

If you want to create an electrical current, which situation would produce a solution capable of this

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?

At a certain temperature the rate of this reaction is first order in hi with a rate constant of : 0.0632s2hig=h2g+i2g suppose a vessel contains hi at a concentration of 1.28m . calculate how long it takes for the concentration of hi to decrease to 17.0% of its initial value. you may assume no other reaction is important. round your answer to 2 significant digits.