Question

which of the following is a pure substance?
gun powder
soda
sugar water
steam

Explanation:

A pure substance has a definite and constant composition. Gun powder is a mixture of sulfur, charcoal, and potassium nitrate. Soda is a solution with various dissolved substances. Sugar - water is a mixture of sugar and water. Steam is water in the gaseous state and is a pure substance as it consists only of water molecules (H₂O).

Answer:

steam