Material Change that Happen Change Happen toto Material WhenMaterial WhenOxygen is absentlighted candlesliced appleOxygen is Present(lighted candleuncovered; sliced(lighted candlecovered; slicedapple exposed toapple soaked inair)water)
Answer (1)
Answer:Changes in Materials: Presence vs. Absence of Oxygen This question explores how the presence or absence of oxygen affects the changes that occur in various materials. We'll examine the specific cases of a lighted candle and a sliced apple. Lighted Candle Oxygen Absent (Candle Covered): When a lighted candle is covered, the flame will eventually extinguish. This is because the candle requires oxygen to burn. The limited amount of oxygen trapped inside the covering is quickly consumed, leading to the flame dying out. The candle itself will remain largely unchanged, except for the portion that was already consumed by the flame. Oxygen Present (Candle Uncovered): A candle burning in the open air will continue to burn as long as there is a supply of oxygen. The flame will consume the wax, producing carbon dioxide, water vapor, and heat. The candle will gradually diminish in size as it burns. Sliced Apple Oxygen Absent (Apple Soaked in Water): A sliced apple submerged in water will experience a slower browning process compared to an apple exposed to air. This is because water limits the amount of oxygen that can reach the apple's surface. While some browning may still occur due to the presence of oxygen dissolved in the water, the reaction will be significantly slower. Oxygen Present (Apple Exposed to Air): When a sliced apple is exposed to air, it undergoes a process called enzymatic browning. This is a chemical reaction triggered by enzymes within the apple's cells. When the apple is cut, these enzymes are exposed to oxygen. The enzymes react with compounds called polyphenols present in the apple, causing them to oxidize and form brown pigments called melanins. This browning is a natural process that occurs to protect the apple from bacteria and fungi. Summary The presence or absence of oxygen plays a crucial role in the changes that occur in materials. In the case of the candle, oxygen is essential for combustion, while in the case of the apple, oxygen triggers a chemical reaction that leads to browning. Key Takeaways: - Oxygen is essential for combustion: Without oxygen, a flame will extinguish.- Oxygen can trigger chemical reactions: In the case of the apple, oxygen causes enzymatic browning.- Water can limit oxygen exposure: This slows down browning in a sliced apple. Further Exploration: - Other Factors Affecting Browning: Factors like temperature, pH, and the presence of certain chemicals can also influence the browning process in apples.- Preventing Browning: There are various methods to prevent or slow down browning, such as using lemon juice, storing apples in airtight containers, or treating them with specific chemicals.- Other Materials and Oxygen: Explore how the presence or absence of oxygen affects other materials, such as iron (rusting) and wood (decay). [4]
