26. Color of water From underwater, looking up In any pool having a white bottom, if more than 3 or 4 feet deep, the water will appear noticeably blue, not colorless.
27. Water structure and its polarity Due to its two lone pairs (unshared electron pairs) and its two bonding pairs, the water molecule has a bent shape derived from a tetrahedron. That bent shape causes water to be polar, so it attracts other polar molecules.
32. Water relatives (Hydrides of congeners, i.e., related elements) Hydrides of chalcogens [stinkogens] Group VIA
33. Melting points & Boiling Points of compounds related to water (hydrides of similar groups). Note the hydrides of F, O, and N are dramatically out of line due to their Hydrogen “bonding”.
34. Ice has a regular arrangement using four Hydrogen “bonds” to each water molecule. This open network leaves large empty spaces, so ice is less dense than liquid water.
35. Solid benzene sinks in liquid benzene (the usual), but ice floats in liquid water (at left).
38. Surface tension & meniscus combine to make “capillary action” Meniscus (Greek means little crescent) is due to the liquid’s adhesion to the glass being greater than the liquid’s cohesion to itself. So, the liquid creeps up at the surface near the glass. The surface tension tries to keep the minimum surface area so the meniscus rises.
40. Surface tension explanation Molecules in interior of the liquid are surrounded by attractive forces, but molecules in the surface layer have only attractions to below. So, it is as if there is a skin having a strong tendency to make a minimum surface area.
41. Reduce surface tension by adding surfactant (soap or detergent). Acute angle Obtuse angle surface surface
49. Hydrologic cycle (Convection on a grand scale) The energy is provided by the sun, but the cycle is also driven by the rising of the light water vapor molecule. Since more evaporation occurs near the equator and condensation occurs more near the poles, this causes wind, weather, storms, and runoff.
