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