2Clues of a Chemical Change A new colour appearseg. Oxygen Indicator Solution
3Clues of a Chemical Change A solid material (called a precipitate) forms in liquidHeat or light is given off
4Clues of a Chemical Change Bubbles of gas are formedThe change is difficult to reverse
5Situation Explanation A piece of dry ice (solid carbon dioxide) is dropped into hot water. Large amounts of white vapour bubble out of the water.PhysicalChemicalExplanationThe bubbles are carbon dioxide gas. There was no chemical change. Just a change in state.
6Situation Explanation When George’s father makes wine from crabapples, bubbles form on the surface of the yeast and fruit mixture.PhysicalChemicalExplanationA chemical change from apple juice to wine, it is no longer the same compound.
7Situation Explanation When margarine is left in a warm place for an extended period of time, it tastes sour.PhysicalChemicalExplanationThe margarine is rotting, which is why it tastes sour.
8Situation Explanation Jane’s father opens up a new deodorant product. The room quickly smells like fresh flowers.PhysicalChemicalExplanationThe deodorant is still deodorant, some particles have changed to vapour which we smell.
9Situation Explanation During a school volleyball game, Jennifer sprains her ankle. Her coach squeezes a bag at room temperature that quickly becomes very cold.PhysicalChemicalExplanationInside the bag a chemical change has occurred which is endothermic.