Is evaporation of seawater to produce salt a chemical change?

Answer 1

Salt evaporating from water would be a physical change.

A physical change occurs when you change something without affecting the molecules it is made of. In your example of salt evaporating from water, the chemicals making up the salt and the chemicals making up the water remain the same; the salt and water still exist, they're just separated from each other.

A chemical change occurs when you change the actual molecular structure of something. For example, when you burn wood, you irreversibly turn wood into heat and ashes; the chemicals in the wood have all been converted into something else.

A good rule of thumb to determine if an action results in a chemical or physical change is this: If I can reverse the action, it is a physical change. When you burn wood or cook meat, you can't go back to fresh wood or raw meat; these are chemical changes. When you mix salt into water or fold paper, you can separate the salt or straighten the paper; these are physical changes.

Answer 2

No, the evaporation of seawater to produce salt is a physical change, not a chemical change. The process involves the separation of water molecules from salt crystals without changing the chemical composition of either substance.

Answer 3

No, it's a physical change.

The water molecules vapourise, leaving behind only the the dissolved ions. The ions remain bonded in their respective compounds, thus no chemical change.

Answer 4

no