Ethan is observing chemical and physical properties of a substance. he heats a substance and observes that the substance turns from a brown solid to a black powder. he refers to several chemistry journals that claim this represents a chemical reaction. from his observation and research, he concludes that the substance goes through a chemical change when heated. how can ethan best defend his conclusion?

Explanation:

A chemical reaction is defined as the reaction which leads to change in chemical composition of the reactants due to which there occurs formation of a new compound.

For example, when Ethan heats a substance and observes that the substance turns from a brown solid to a black powder then it means heating has lead to a chemical change in the brown solid because of which it has turned into a black powder.

Whereas if there occurs no change in chemical composition of the reactants then we can say that a physical change has occurred.

For example, change in shape, size, mass etc of a substance are all physical changes.

Hence, we can conclude that Ethan best defend his conclusion as a chemical change.

gas

explanation:

smoke is the matter of a gas

(b) which contains higher levels of vitamin b, oranges or spinach?

explanation:

you can eliminate a, c, and d because they are questions based on opinions.