Science Unit B

4. A system in which gases and reactants can escape and be contaminated
5. A reaction in which two or more substances combine to change the properties of the substances before non-reversible
7. Determines number of protons and electrons
8. Non-Reversible change
9. The substance is made up of only one atom
12. Reversible change
14. metal + non-metal
15. A chemical reaction that occurs with oxygen that is fast
16. A chemical reaction that occurs with oxygen that is slow
17. releases heat
18. Anything on the periodic table
19. Democritus figured out an atom is … John Dalton experimented this
20. The mass of one atom in the element
22. This represents the element on the periodic table
23. Used in the chemical naming of a molecular compound
24. this is to ensure the user of the product is safe while in the use product in a workplace
25. When reactants combine creating this

1. an organic catalyst
2. substances combined with each other to create a product and chemical reaction
3. non-metal + non-metal
6. Fused in the nucleus with protons
10. absorption of heat
11. Concentration, catalyst, surface area and temperature all affect the …
13. No gases can escape nor can it be contaminated
21. The number in a formula that represents the amount of the element present