Chemistry

3. A colorless gas with a characteristic pungent smell
4. Fool's gold
7. A substance used to speed up a chemical reaction
8. The use of pesticides and insecticides are types of ____ control to protect food crops from unwanted pests or insects
11. Compromises only about 0.05% of the earth's crust by mass but easily obtained
12. Is a process in which plants replenish oxygen in Earth's atmosphere
13. nitrogen ____ is the process of organisms to convert atmospheric nitrogen to a form that can be used by plants
15. The movement of nitrogen and nitrogen compounds from the air to the soil and back forms this cycle
16. The result of heating white phosphorous to about 300C in the absence of air
17. Addition of hydrogen to double (or triple) bonds
18. Makes up 78% of the volume of air

1. Most abundant element in earth's crust
2. The antibacterial action of hydrogen peroxide is due to highly reactive molecules called
3. Two or more forms of the same element that differ in properties but exist in the same physical state
5. Ammonium ____ was commonly used as smelling salts to revive someone who has fainted
6. The ____process is when superheated water injected into the bed of sulfur containing rock through the outermost of three concentric pipes causing sulfur to melt and form a liquid pool
9. Nitrogen is found in all living things in the form of ___ and nucleic acids
10. the most important commercial method of preparing hydrogen in the US
14. The most abundant element in the universe
17. The ammonia used for fertilizer production is synthesized by the ____ process