What Do These Two Changes Have In Common? Burning A Candle Newly Poured Concrete Becoming Hard Select All That Apply. Chemical Change Or Physical Change Or Caused By Heating Or Caused By Cooling?
Introduction
Chemical and physical changes are two fundamental concepts in chemistry that help us understand the transformations that occur in matter. In this article, we will explore the commonalities between two seemingly unrelated changes: burning a candle and newly poured concrete becoming hard. We will examine whether these changes are chemical or physical, and whether they are caused by heating or cooling.
What is a Chemical Change?
A chemical change, also known as a chemical reaction, is a process in which one or more substances are transformed into new substances with different properties. Chemical changes are often accompanied by changes in color, odor, or temperature. Examples of chemical changes include combustion, rusting, and fermentation.
What is a Physical Change?
A physical change, on the other hand, is a process in which a substance changes its state or properties without undergoing a change in its chemical composition. Physical changes are often reversible and do not involve the formation of new substances. Examples of physical changes include melting, boiling, and dissolving.
Burning a Candle: A Chemical Change
When a candle is burned, the wax undergoes a chemical change, releasing heat, light, and carbon dioxide gas. The wax molecules are broken down and reformed into new molecules, resulting in a change in the chemical composition of the substance. This process is an example of combustion, a type of chemical reaction that involves the reaction of a fuel with oxygen.
Newly Poured Concrete Becoming Hard: A Physical Change
When newly poured concrete is left to set, it undergoes a physical change, known as hydration. The cement particles in the concrete react with water to form a hard, solid substance. This process is an example of a physical change, as the chemical composition of the concrete remains the same, but its properties change.
Caused by Heating or Cooling?
Both burning a candle and newly poured concrete becoming hard are caused by heating. When a candle is burned, the heat from the flame causes the wax to melt and undergo a chemical change. Similarly, when newly poured concrete is left to set, the heat from the surrounding environment causes the cement particles to react with water, resulting in a physical change.
Conclusion
In conclusion, burning a candle and newly poured concrete becoming hard are two seemingly unrelated changes that share a commonality: they are both chemical or physical changes caused by heating. While the candle undergoes a chemical change, the concrete undergoes a physical change. Understanding the differences between chemical and physical changes is essential in chemistry, as it helps us predict and explain the behavior of matter.
Key Takeaways
- Burning a candle is an example of a chemical change, while newly poured concrete becoming hard is an example of a physical change.
- Both changes are caused by heating.
- Chemical changes involve the formation of new substances, while physical changes do not involve a change in chemical composition.
Frequently Asked Questions
Q: What is the difference between a chemical change and a physical change?
A: A chemical change involves the formation of new substances, while a physical change does not involve a change in chemical composition.
Q: What is an example of a chemical change?
A: Burning a candle is an example of a chemical change.
Q: What is an example of a physical change?
A: Newly poured concrete becoming hard is an example of a physical change.
Q: What causes both burning a candle and newly poured concrete becoming hard?
Q: What is the difference between a chemical change and a physical change?
A: A chemical change involves the formation of new substances, while a physical change does not involve a change in chemical composition. Chemical changes are often accompanied by changes in color, odor, or temperature, and are often irreversible. Physical changes, on the other hand, are often reversible and do not involve the formation of new substances.
Q: What is an example of a chemical change?
A: Burning a candle is an example of a chemical change. When a candle is burned, the wax undergoes a chemical reaction, releasing heat, light, and carbon dioxide gas. The wax molecules are broken down and reformed into new molecules, resulting in a change in the chemical composition of the substance.
Q: What is an example of a physical change?
A: Newly poured concrete becoming hard is an example of a physical change. When concrete is left to set, the cement particles react with water to form a hard, solid substance. This process is an example of a physical change, as the chemical composition of the concrete remains the same, but its properties change.
Q: What causes both burning a candle and newly poured concrete becoming hard?
A: Both changes are caused by heating. When a candle is burned, the heat from the flame causes the wax to melt and undergo a chemical change. Similarly, when newly poured concrete is left to set, the heat from the surrounding environment causes the cement particles to react with water, resulting in a physical change.
Q: Can a physical change be caused by cooling?
A: Yes, a physical change can be caused by cooling. For example, when water is cooled, it undergoes a physical change from a liquid to a solid, a process known as freezing.
Q: Can a chemical change be caused by cooling?
A: No, a chemical change is not typically caused by cooling. Chemical changes are often caused by heat, light, or other forms of energy that break or form chemical bonds.
Q: What is the difference between a chemical reaction and a physical change?
A: A chemical reaction involves the formation of new substances, while a physical change does not involve a change in chemical composition. Chemical reactions are often accompanied by changes in color, odor, or temperature, and are often irreversible. Physical changes, on the other hand, are often reversible and do not involve the formation of new substances.
Q: Can a chemical reaction be reversible?
A: Yes, some chemical reactions can be reversible. For example, the reaction between hydrogen and oxygen to form water is a reversible reaction, as the water can be broken down back into hydrogen and oxygen.
Q: Can a physical change be irreversible?
A: Yes, some physical changes can be irreversible. For example, when a liquid is frozen, it undergoes a physical change from a liquid to a solid, and the process is often irreversible.
Q: What is the importance of understanding chemical and physical changes?
A: Understanding chemical and physical changes is essential in chemistry, as it helps us predict and explain the behavior of matter. It also helps us understand the properties and characteristics of different substances, and how they can be changed or transformed.
Q: What are some common examples of chemical changes?
A: Some common examples of chemical changes include combustion, rusting, and fermentation. These changes involve the formation of new substances and are often accompanied by changes in color, odor, or temperature.
Q: What are some common examples of physical changes?
A: Some common examples of physical changes include melting, boiling, and dissolving. These changes do not involve the formation of new substances and are often reversible.