Question

Which of these is an example of a physical change?

sugar dissolving in warm water
iron rusting in the presence of moist air
wood burning in the presence of oxygen
baking soda reacting with acid to form a gas

Answer 1

The physical change would be the sugar dissolving in water because no reaction is occurring.

Answer 2

sugar dissolving in warm water is an example of physical change.

physical change is doesn't alter the composition or the identity of the substance .
That's mean when you dissolves sugar in water, after a while the object will be the same which mean that the component doesn't change