Which caused a change in matter. select each procedure that is likely a chemical change. salt crystals were crushed into a fine powder. bubbles were produced when iron was placed in acid. two liquids were combined, and a solid appeared. a piece of metal melted when it was heated. a white substance turned blue when water was added.

These 2 are physical changes:

Salt crystals were crushed into a fine powder.

A piece of metal melted when it was heated.

These are likely to be chemical changes:

Bubbles were produced when iron was placed in acid.

Two liquids were combined, and a solid appeared.

A white substance turned blue when water was added.

pure water does not conduct electricity very well. however, when certain substances are dissolved in water, the solution does conduct electricity. you can make a simple device that shows how well a solution conducts electricity. this device uses a flashlight bulb to indicate how well the solution conducts electricity. the better the solution conducts electricity, the brighter the bulb will glow.

explanation:

it means there are 3 atoms of oxygen