Question 4(multiple choice worth 1 points) [04.01]two test tubes each contain a colorless liquid. one of the test tubes contains water and the other nitric acid. when sucrose is added to the water, the sugar disappears and the liquid remains colorless. when copper is added to the nitric acid, the copper disappears but the liquid turns blue and gives off a brown gas. which of the following best explains what happened in both test tubes? the reactants in both test tubes underwent physical changes. a physical change happened in the water, and a chemical change happened in the nitric acid. two chemical changes occurred in the test tubes but with different products being formed. the sugar dissolving was a chemical change, and the release of a gas was a physical change.