Question

instructions: for each test item, identify the choice that best completes the statement or answers the question. question 16 3 pts which of the following contains a clue that a chemical change is occurring? o iron glows when heated o a gas is formed when vinegar and baking soda are mixed o melted wax hardens when poured into cold water o water boils

Explanation:

A chemical change results in the formation of a new substance. When vinegar and baking soda are mixed, a gas (carbon - dioxide) is formed, indicating a chemical reaction. Water boiling is a physical change (liquid to gas), melted wax hardening is a physical change (liquid to solid), and iron glowing when heated is a physical change (change in temperature and appearance without new substance formation).

Answer:

C. a gas is formed when vinegar and baking soda are mixed