# of bonds with hydrogen B17 HW Debrief ANALYSIS: B33 Q3 Q4 Q5 some atoms can make more than one bond (O, N, C) element atomic # # of bonds with hydrogen Si 14 4 Se 34 2 I 53 1 (how figure out?) As 33 3 can you make HO2? no – oxygen would have an "empty" bond

Q6 Q7 sketch of a molecule has more information showing where bonds are, chemical formula does not show bonds

density compared to other substance (sink or float in water?) LEARNING TARGET: I can use collected evidence from chemical / physical property tests to identify an unknown plastic sample. NOV 6 / 7 Act B18 Properties of Plastic CHALLENGE Q How do the physical and chemical properties of plastics affect their uses? VOCAB: physical / chemical properties relative density (should know already) density compared to other substance (sink or float in water?)

From Act 12 why would making a drink container out of plastic be good? strong, light, cheap, easy to shape/color, won't break Physical Properties of plastics? flexible, strong, heat resistant, relative density to water or other liquids (color not a PP as humans can change it)

Four Common Plastics Color Key

PROCEDURE: B 35-37 and summarize PROC AND DATA MATERIALS: PROCEDURE: B 35-37 and summarize DATA: WS 18.1 DO NOT LEAVE OPEN VIALS SITTING ON TABLE (they get knocked over) do activity FYI - to get small plastic out of vial, turn upside down and let square lay flat on inside of cap – then CAREFULLY tip vial back until liquid is in bottom and take cap off with square stuck to it neat trick!!

Which of the four types of plastic you tested do you think is used most today and why? using HandOuts: PP 21% of plastics (straws, bottle caps/lids) or HDPE 19% of plastics (milk + detergent bottles)

ANALYSIS: B37 Q2 Q3 a. PVC most dense as it sinks in saltwater (others floated) b. PP least dense as it floated on alcohol/water mixture c. 0.80 0.90 1.0 1.1 alcohol alc/water water saltwater PP HDPE PS PVC mystery plastic is PS – floats above saltwater but sinks through water and alcohol/water mix, soft with heat and acetone

Q4 Best container for: a. nail polish (high acetone) = PP or HDPE (acetone "proof") b. dishwasher-safe food container = PP or HDPE (heat "proof") c. sports drink = HDPE (heat "proof" in sunlight, no creasing)

Which is the best material for making a drink container? A: ANS CHALLENGE Q Which is the best material for making a drink container? A: HOMEWORK 1. B37 Qs 2-4 (10pts, next class) HDPE best for drink container