Grade 7 Bilingual - Unit 2 crossword

4. Substances used in chemical reactions to detect, measure, examine, or produce other substances.
6. When something falls down suddenly, usually because it's not structurally sound.
7. How clearly objects can be seen, often used in the context of weather conditions.
9. This process happens when something burns, combining with oxygen and releasing heat and light.
12. Something that comes first, often serving as a preparation or introduction.
15. This type of reaction involves the combining of a substance with oxygen.
16. A common substance, chemically known as sodium chloride, often used to season food.
18. A chemical reaction that releases heat into its surroundings
19. Gases or particles that are released into the air, often from vehicles or factories.
20. The condition of the atmosphere at a particular place and time, with respect to heat, cloudiness, dryness, sunshine, wind, rain, etc.
22. A branch of mathematics dealing with data collection, analysis, interpretation, and presentation.

1. A substance that readily undergoes chemical changes
2. A paper with a rough surface used for smoothing or polishing
3. A type of plastic that is made from plant or other biological materials instead of petroleum.
5. Huge, slow-moving masses of ice found in mountains or near the poles.
8. A large rock, typically one that has been worn smooth by erosion.
10. This substance, like gasoline or wood, is burned to produce energy
11. Chemically inactive
13. This type of chemical reaction absorbs heat
14. To scatter or fade away
17. The act of clearing a wide area of trees.
21. Iron does this when it reacts with oxygen and water over time, forming a reddish-brown coating