When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.

When a candle burns, both physical and chemical changes occur simultaneously:
1. Chemical Change:
– Combustion Reaction: The burning of the candle involves a chemical change known as combustion. The wax (composed of hydrocarbons) reacts with oxygen in the air to produce carbon dioxide gas (CO₂) and water vapor (H₂O) through a combustion reaction. The chemical equation for this combustion is:
C₂₅H₅₂(wax) + O₂ oxygen → CO₂ carbon dioxide + H₂ O water vapor

2. Physical Change:
– Melting and Solidification: Prior to burning, the solid wax melts due to the heat of the flame. This melting is a physical change as it alters the state of the wax from solid to liquid. Upon extinguishing the flame, the melted wax cools and solidifies back into a solid state, which is another physical change.

Another familiar process involving both physical and chemical changes is “Cooking an Egg”:
1. Chemical Change:
– Protein Denaturation: When an egg is heated, the proteins within the egg undergo a chemical change called denaturation. The heat causes the proteins to unfold and change their structure, resulting in the solidification of the egg white (albumen) and the yolk (due to the denaturation of proteins).

2. Physical Change:
– State Changes: Similar to the candle, physical changes occur during cooking an egg. The egg transitions from a liquid state to a solid state as a result of the denaturation process. Additionally, as the egg cooks, changes in texture, color, and volume occur, representing physical transformations.

Both the candle burning and cooking an egg illustrate processes where chemical changes (combustion or protein denaturation) and physical changes (melting/solidification or state changes) take place simultaneously, showcasing a blend of both types of alterations.