Learning Target:Design and Plan a Scientific Investigation to Compare the Structure of Substances at the Bulk Scale to Infer the Strength of Electrical Forces Between Particles….and…Communicate scientific and technical information about why the molecular level structure is important in the functioning of designed materials
Must Do:Write a brief statement about your knowledge of
molecular (covalent) vs. ionic compounds
10th Grade Chemistry: 1/22/14
Agenda:•Must Do•WWD•Brief Lesson•Lab!!!!
What’s the caption?
WWDPicture Clues….one word, four syllables
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Polarity!Definition
Noun
(1) The presence of or having distinct and opposite poles
(2) The condition of having contrasting properties or direction
(3) (chemistry) The tendency of forming distinctive opposing charges based on the orientation of chemical bonds and spatial structure of the molecule
How to tell the difference between a molecular and ionic compound
Use the periodic table!
Compounds and Chemical Formulas
Molecule - A single particle, contains two or more nonmetal atoms; covalently bonded
Formula Unit – a particle containing a metal with a nonmetal; ionicly bonded
Chemical formulas – give the number of atoms of each element in a compound
Identifying Ionic and Molecular Compounds
Which of the following compounds would you expect to be ionic: N2O, Na2O, CaCl2, SF4?
Which of the following compounds are molecular: CBr4, FeS, P4 O6, PbF2 ?
Which combination is likely to produce an ionic compound?
C and H
S and Cl
Ca and F
Br and I
Xe and F
Which combination is likely to produce an ionic compound?
C and H
S and Cl
Ca and F
Br and I
Xe and F
Solubility Important concept for the lab
Do you expect that ionic compounds will dissolve in non-polar, somewhat polar, or polar liquids?
Will molecular compounds dissolve in non-polar, somewhat polar or polar liquids? Alcohol in water? Acetone in water? Sugar in water? Sugar in Acetone? Mineral oil in water, acetone, alcohol?
In general “like dissolves like”
Useful LinksPolarity Index
Water Solubility DataSolubility TableSolubility Chart
Lab!
•Build the Best BatteryMake a matrix of materials and measure the electrical properties of your cell
Try to get the most voltage out of your Cell (cells….this is a hint).
The winning group gets to do a victory dance
Matrix Example
Lab Rules
Lab Rules ContinuedPlease dump waste in the orange bucket
Go easy on the Isopropyl and acetone
Try not to spill!