Hey there! :D
Which of the following is a chemical change?
A chemical change is a change that alters the makeup of a substance or something. It changes what it is made of. You cannot alter chemical changes.
Boiling water can go back to regular room temperature water. This is not a chemical change.
Melting a cube of ice is not a chemical change. We can freeze the water again to make it ice.
Dissolving 10 grams of salt in water is not a chemical change. You can boil the water and split the salt and water. People do this with Ocean water, to make it drinkable.
Splitting water into hydrogen and oxygen is a chemical change. You change the makeup of the water. It is now separate hydrogen and oxygen. It is not water anymore. "D" is the answer.
I hope this helps!
~kaikers