Chemical Reactions

3. A compound made from copper, carbon, and oxygen.
7. A type of reaction where one substance breaks down into two or more simpler substances (e.g., CaCO₃ → CaO + CO₂).
10. A change in shape or state that doesn’t create a new substance (like melting).
13. A number placed in front of a chemical formula to balance a chemical equation (e.g., 2H₂ + O₂ → 2H₂O).
14. What is the process called when something reacts with oxygen and releases heat and light?
15. A substance that feels slippery and turns litmus paper blue.
16. A solution used to test for carbon dioxide.

1. A substance formed in a chemical reaction.
2. A change that makes a new substance (like burning wood).
4. A substance that tastes sour and turns litmus paper red.
5. What do we call a reaction between an acid and an alkali?
6. What happens when a solid mixes into a liquid?
8. The scale we use to measure how acidic or alkaline a substance is.
9. A small number written below a chemical symbol to show how many atoms of that element are in a compound (e.g., O₂).
11. A substance that reacts in a chemical reaction.
12. The short letter or letters used to represent an element (e.g., H for hydrogen).