Across
- 1. 21% of clean dry air
- 5. found in the ore zinc blende
- 6. catalyst used in fermentation of glucose
- 8. extracted from heamatite
- 10. reducing agent in blast furnace
- 11. compound found in clean dry air
- 12. form an amphoteric oxide
Down
- 2. 78% percent in atmosphere
- 3. responsible for acid rain
- 4. metal used in brass
- 7. main impurity in iron ore
- 9. stored under oil
- 13. catalyst used in hydrogenation