Physical change is the change we can see with our eyes. Chemical change is the change that we cannot see. Examples: physical change: The Polar ice caps are melting, and we can see that as it happens. Chemical change: The cooking of an egg or some combustion, like a fire. We can't see the chemicals coming from the fire, but there are chemicals coming from what is being burned and is being released into the air that we cannot see.
Any salt, even though it reacts with water, will precipitate out completely when the water is completely evaporated. If you start with 50 grams of salt, you will end up with 50 grams of salt.
I would suggest you to use this instead.
Just place the known substance for example O2 Oxygen as they are asking you, and see where the diagram takes you.
So the answer would be 2 because you’d look at the coefficients of the balanced equation up there. H2O
I hope that was helpful, if you have more questions please ask!
Splitting is chemical liquid at room temp is physical density is physical and reactions are chemical