whats the answer How are chemical changes different from physical changes?(1 point) Responses They form new substances. They form new substances. They include shifts in the phase of matter. They include shifts in the phase of matter. They are reversible. They are reversible. They involve heat.
The correct answer is: They form new substances.
Chemical changes differ from physical changes in several ways:
1. Formation of new substances: Chemical changes result in the formation of new substances with different chemical properties. In contrast, physical changes do not produce new substances.
2. Phase shift of matter: Physical changes involve shifts in the phase of matter, such as changing from solid to liquid or from gas to liquid. On the other hand, chemical changes do not necessarily involve phase shifts.
3. Reversibility: Physical changes are often reversible, meaning that the original substance can be restored after the change. In contrast, chemical changes are usually irreversible, and it is not possible to regain the original substances once they have undergone a chemical reaction.
4. Involvement of heat: Chemical changes often involve the release or absorption of heat energy. Physical changes may or may not involve heat, depending on the specific circumstances.
Therefore, the correct answer would be: Chemical changes differ from physical changes as they form new substances, do not necessarily include shifts in the phase of matter, are often irreversible, and involve the release or absorption of heat.
The correct answer is: "They form new substances."
To understand why chemical changes are different from physical changes, let's break down the options provided:
1. "They form new substances" - This is the correct answer. Chemical changes involve a rearrangement of atoms and molecules, resulting in the formation of entirely new substances with different chemical properties. For example, when wood burns, it undergoes a chemical change where it reacts with oxygen to form carbon dioxide and water.
2. "They include shifts in the phase of matter" - This option refers to physical changes, not chemical changes. Physical changes involve alterations in the state or appearance of matter without any change in the chemical composition. For instance, when water boils and converts into steam, it undergoes a physical change.
3. "They are reversible" - Reversibility is not a defining characteristic of chemical changes. While some chemical reactions can be reversed under specific conditions, many chemical changes are irreversible. It primarily depends on the specific reaction and the conditions involved.
4. "They involve heat" - Heat can be involved in both chemical and physical changes, so this option is not specific to chemical changes. Physical changes, such as melting or boiling, also often involve the addition or removal of heat.
In summary, the key distinction between chemical changes and physical changes lies in the formation of new substances during chemical changes, while physical changes involve alterations in the physical properties of matter without any changes in its chemical composition.