How are chemical changes different from physical changes? (1 point)
They are reversible.
O They include shifts in the phase of matter.
They form new substances.
O They involve heat.
The correct answer is: They form new substances.
Chemical changes are different from physical changes because they form new substances. Physical changes, on the other hand, do not form new substances but rather involve changes in the state of matter or the rearrangement of particles.
To determine how chemical changes are different from physical changes, we can examine the answer choices and eliminate incorrect options.
Let's go through each option one by one:
1. "They are reversible." - This is not necessarily true for chemical changes. Chemical changes usually result in the formation of new substances, which are often difficult to reverse.
2. "They include shifts in the phase of matter." - While this can happen in both physical and chemical changes, it is not a defining characteristic that distinguishes between them.
3. "They form new substances." - This is correct. Chemical changes involve the rearrangement of atoms and molecules, leading to the formation of new substances. This is a key difference between chemical and physical changes.
4. "They involve heat." - While heat can be involved in both types of changes, it is not a defining characteristic for distinguishing between them. Heat can be added or released in physical and chemical changes, depending on the specific process.
Therefore, the correct answer in this case would be: Chemical changes form new substances.