Which scenarios are examples of physical changes? Check all that apply.

1-Wood is burned in a campfire and is turned into ash and smoke.
2-Silicon is cut into tiny pieces for computer chips.
3-Lead is melted to form pellets.
4-Liquid water freezes to form ice.
Yeast turns sugar into energy, water, and carbon dioxide gas.

1) a. water molecule breaks up into hydrogen and oxygen on passing electricity. does this involve breaking intermolecular or intramolecular forces of attraction. explain b. on boiling water changes to water vapor. does this involve breaking intermolecular or intramolecular forces of attraction. explain methanol evaporates faster than water. contrast the intermolecular forces and the vapor pressures of methanol and water?