It’s based on electronegativity! Distribution of charge!

Polar A. Uneven distribution of charge B. Example: Water C. Each atom either has a partial positive or partial negative charge A. Partial negative = more likely to attract electrons B. Partial positive = more likely to give up electrons

Nonpolar A. Even distribution of charge B. Example: CCl 4

Polarity Slight charges in a molecule Like a magnet v=iJxxyCBTeNs (balloon and water) v=iJxxyCBTeNs ?v=ASLUY2U1M-8 (polarity – TED-ED) ?v=ASLUY2U1M-8

Polarity in Bonds A. Polar covalent bond – uneven sharing of electrons 1. 1 atom pulls the electron more towards itself slightly B. Nonpolar covalent bond – even sharing of electrons 1. Neither atom pulls an electron more towards itself C. Ionic bond – a large amount of uneven charge D. All are due to electronegativity – the tendency of electrons to go more towards one atom

Electronegativity trend

Dissolving A. “Like dissolves like” rule B. Polar dissolves Polar C. Nonpolar dissolves Nonpolar D. They don’t dissolve each other

Demos: Density column Lava lamp (polar/nonpolar – crash course)

(Properties of Water – Ricochet Science) Don’t forget – It’s a universal solvent! (What happened if you stopped drinking water? – ASAP) (Can you drink too much water? – ASAP)

WATER IS unique! A. Its properties are due to polarity A. Results in hydrogen bonding H = partially (+) N or O= partially (-) B. Weak by themselves, but a lot are strong

What could this be?

1. Surface Tension A. Surface of a liquid that can resist a force by contracting B. “Floating” on water  Hydrogen bonds don’t all break (water strider) (Jesus Lizard - general) (Jesus Lizard – how it works

What could this be?

2. Temperature moderation (heat capacity) A. Water takes a lot of energy to raise its temperature B. H bonds need to be broken before water can change state

What could this be?

3. Cohesion A. Attractive force that holds molecules of 1 substance together B. Brings molecules of a substance together

What could this be?

4. Adhesion A. Attractive force between two particles of different substances B. Move towards a surface

This is like glue

What could this be?

Capillary action 1. Upward movement of water 2. Defies gravity and travels up a narrow tube Ex: Up the stem in plants 3. Combines cohesion, adhesion and surface tension

Density of ice Why does ice float in water? A. Ice is less dense than liquid water. B. Large spaces between water molecules = floats (TED-ED why does ice float on water)

Properties of Water Lab Videos (Crash Course) (Richard Kern) (Ricochet Science)