Decomposes by electrolysis a physical or chemical change

Which of the following elements is a representative element? a. chromium (cr) b. aluminum (al) c. mercury (hg) d. silver (ag)

Condensation happens when water vapor cools. true or false? ?

4. propanol and isopropanol are isomers. this means that they have a) the same molecular formula but different chemical properties. b) different molecular formulas but the same chemical properties. c) the same molecular formula and the same chemical properties. d) the same molecular formula but represent different states of the compound