Classify each change as physical or chemical. a. Natural gas burns in a stove. b. The liquid propane in a gas grill evaporates because the valve was left open. c. The liquid propane in a gas grill burns in a flame. d. A bicycle frame rusts on repeated exposure to air and water.

Video transcript

Hi everyone here we have a question asking us to classify the following as physical or chemical changes. A physical change. The composition does not change a chemical change. The composition does change. So we have a water condenses on the surface of a cold glass. When water is condensing, it is simply changing forms so we can, it's still water. So our composition is not changing. So that is a physical change. Rest forms on the surface of an iron nail. Once that rest forms, we can't get the iron back because the composition has changed because it is a chemical change. Black smoke rises when a candle is burned. When a candle is burned, the wick is being burned which is releasing that black smoke and its composition is changing to release that black smoke. So that is a chemical change. A drop of alcohol evaporates on a table. That is a physical change. Because the composition, it's not changing, its form is simply changing. It's going from a liquid to a gas. So that is a physical change. So these are our final answers. Thank you for watching. Bye.