Question

1. chemical change can be identified by specific observations. which would most likely indicate a chemical change? a mineral is crushed into fine dust and mixed with water. a light green powder forms on the outside of a penny. rock is slowly worn away by the action of wind and sand. salt is dissolved in water.

Explanation:

A chemical change results in a new substance being formed. Salt dissolving in water is a physical - change as it is just a change of state in solution. Rock being worn away by wind and sand is physical weathering. A light green powder forming on the outside of a penny is a chemical change as copper in the penny reacts with substances in the air to form a new substance (copper carbonate). Crushing a mineral into dust and mixing with water is a physical change.

Answer:

A light green powder forms on the outside of a penny.