1. Compounds and Mixtures 8 th Grade Science SWMS

2. Compound A chemical substance consisting of two or more different chemical elements Examples: (what elements?) Water = H 2 O Vinegar = CH 3 COOH  Baking Soda = NaHCO 3 ***1***

3. Chemical Formula Series of chemical symbols used to represent a compound Examples: – Sucrose (C 12 H 22 O 11 ) – Hydrochloric Acid (HCl) – Ethanol (C 2 H 5 OH)  Subscript  Small number used to show number of atoms/elements present **2**

4. Mixtures Combination of two or more pure substances that are NOT chemically combined. No chemical change (reaction) takes place! – Ex: Tap Water has minerals mixed in

5. Element, Compound, or Mixture? Copper

6. Element, Compound, or Mixture? Copper

7. Element, Compound, or Mixture? Table Sugar

8. Element, Compound, or Mixture? Table Sugar

9. Element, Compound, or Mixture? Diamond

10. Element, Compound, or Mixture? Diamond

11. Element, Compound, or Mixture? Salt

12. Element, Compound, or Mixture? Salt

13. Element, Compound, or Mixture? Salad

14. Element, Compound, or Mixture? Salad

15. Element, Compound, or Mixture? Pure Water

16. Element, Compound, or Mixture? Pure Water

17. Compounds look different When elements form compounds  Different properties than when uncombined For Example: -Sulfur = Yellow Rock -Silver = Shiny Metal

18. Silver Sulfide looks different! End Product: Silver (Ag) + Sulfur (S)  Silver Sulfide (Ag 2 S) Silver Sulfide = Black Tarnish

19. Totaling Atoms Using PSEC Parentheses Subscripts Extras Coefficients Count up the total number of atoms inside the parentheses Multiply the total number of atoms inside the parentheses by the subscript value Add any extra atoms that were not yet accounted for to the total Multiply the total number of atoms (from PSE) by the coefficient

20. Examples Parentheses Subscripts Extras Coefficients 2Ba(NO 3 ) 2 4(NH 4 ) 3 PO 4 P – 4 atoms total N  1 O  3 4 atoms S – 8 atoms total (4)(2) = 8 atoms E – 9 atoms total 8 + 1 = 9 atoms C – 18 atoms total (9)(2) = 18 atoms P – 5 atoms total N  1 H  4 5 atoms S – 15 atoms total (5)(3) = 15 atoms E – 20 atoms total 15 + 5 = 20 atoms C – 80 atoms total (20)(4) = 80 atoms

21. Homework (10/15, 10/16) Search and find 5 common compounds hiding in your house. For each one you will provide: – The common name of the compound – The elements that make up your compound (name and symbol) – How many total atoms in a single molecule of your compound.