Question

List four clues that suggest a chemical change is taking place, and provide an example for each.

Answer 1

Color Change- Bananas turn from yellow to brown
Odor Change- Milk turns rotten sour smell
Temperature Change- Burning Wood
Bubbles- antacid Tablet placed in water
Formation of Solid- Formation of shells of clams

Answer 2

Answer : Chemical change can be easily characterized by the formation of new substance and which cannot be reversed to get the reactant using any physical methods. There are several clues which suggest that chemical change has occurred.

1) Formation of a precipitate - When a solution is mixed with another solution and the product is formed in the form of solid which precipitates at the bottom.

2) Change of composition - Paper when burns into ashes is an example of compositional change.

3) Change in temperature or energy - When an exothermic or endothermic reaction occurs it absorbs or releases heat respectively.

4) Decomposition of organic matter - Milk used for making cheese.