Which is NOT an indicator of a chemical change? Heat or light is produced. State of matter changes. A new substance is formed. A gas is formed.

The choice that is not an indicator of a chemical change is " State of matter changes". More common than not, chemical reactions produce energy in the form of light or heat. Along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid). Technically, a change in state is a physical change unless it also involves one of the other choices.