i think he meant state changes in which the atoms or molecules don't change but their energy and speed change

Sure. The things you listed are all state changes - changes between the states of matter - solid, liquid, gas, and (not mentioned in your post) plasma.

Evaporation is liquid to gas. Sublimations is straight from solid to gas (think “what dry ice does”). State changes are driven by a combination of the amount of energy in a substance and pressure. However, when things change states their molecular structures don’t change. Water vapor, liquid water, and solid water (ice) are all the same chemical substance (H2O) just in different states.

For a chemical change, molecules must change. This means that atoms must break and/or create bonds with one another. This happens generally by sharing or exchanging electrons in the outermost shell (called the valence shell) of the atoms. So there will be DIFFERENT molecules after a chemical change then there were at the beginning. Examples of this include burning paper (in which cellulose breaks down to glucose and glucose breaks down to CO2 and H2O) or photosynthesis (which is sort of the reverse chemical reaction) in which plants use CO2 and H2O to make glucose (C6H12O6).

Oh. I missed distillation in your post. Sorry. In distillation we use the fact that different substances change states at different temperatures in order to separate them (example, separating water from alcohol or the various types of compounds that make up oil (petroleum) into constituent parts like kerosene, diesel, or gasoline. However, generally the substances themselves don’t change chemically.

Evaporation is changing something from a liquid to a gas. Liquid water into water vapor is still water (H2O)

Distillation is removing impurities by heating and cooling. Think of distilling tap water and having salt buildup left behind. Or distilling whiskey to get rid of impurities. It's still whiskey/water at the end, just less junk in it.

Sublimation is going from a solid to a gas, like dry ice (CO2) into regular CO2 gas. All the same stuff, just in a different state.

What you were talking about would be more like electrolysis of water. With stainless steel, tap water and a battery, you can put two pieces of stainless steel (or gold, silver, or platinum, but stainless is easier to find. I used hose clamps when I did this) in water and connect a battery across them. The energy of the batter actually splits the water molecule (H2O) into hydrogen (2H) and oxygen (O) which is actually splitting the molecule into its atoms.

You can tell it split and not just water vapor because you can put a lighter to the bubbles coming from the - side and they should make a small "pop" noise, which is the hydrogen burning with the oxygen into the air and making water vapor. If you collect a bunch of the bubbles from the + side, you can re-light a blown out match/candle that's still hot because it's pure oxygen.

It's weird that water can be broken down into two very volatile fire parts when water is used to put out fire, but that's chemistry for you.

So yeah, long story short, splitting (some) molecules is fairly easy to do and makes some drastically different properties than the original thing!