Question

what is a sign of a chemical change? a) compressing b) boiling c) tearing d) stretching. what happens to the atoms of a substance in a physical change? a) atoms bond together differently b) atoms change their arrangement and motion c) atoms get bigger d) atoms get smaller. what happens to the atoms of a substance in a chemical change? a) atoms bond together differently b) atoms get bigger c) atoms change their arrangement and motion d) atoms get smaller. which of the following changes is a physical change of matter? a) paper burning b) water evaporation

Explanation:

1. A chemical change involves the formation of new substances with different chemical properties. Burning is a chemical change. Among the options given for the first question, combustion is a chemical - change sign. Compressing, tearing, and stretching are physical changes.
2. In a physical change, the atoms of a substance change their arrangement and motion, but the chemical bonds between atoms do not break and reform in a new way.
3. In a chemical change, atoms bond together differently to form new substances.
4. A physical change of matter is a change in which the substance's chemical composition remains the same. Water evaporation is a physical change as water changes from the liquid to the gaseous state without changing its chemical composition (H₂O). Paper burning is a chemical change as new substances like carbon - dioxide and ash are formed.

Answer:

1. Combustion
2. b) Atoms change their arrangement and motion
3. a) Atoms bond together differently
4. b) Water evaporation