Chemistry CFE Practice Test 2026 – All-in-One Guide to Excel in Your Exam!

The main idea is telling apart physical changes from chemical changes. A physical change alters how a substance looks or what state it’s in, but it doesn’t change what the substance actually is. Examples include melting ice into water, crushing a tablet, or stretching a piece of metal—everything involved is still the same substance at the end, just rearranged or in a different form. Because no new substance forms, these changes are usually reversible by physical means.

Chemical changes, on the other hand, involve forming new substances with different compositions, which happens when bonds are broken and new ones are made—like burning wood to ash or iron reacting with oxygen to form rust. This is what makes chemical changes distinct from physical changes.

So a change that alters appearance or state without changing the substance’s composition fits the idea of a physical change. A physical property describes what the substance is like without changing it, while a chemical property describes how it behaves in reactions to form new substances.