BIOL 1001 Chapter : Chapter 2 Atoms Molecules And Life Part 2 Of 2
Document Summary
Water makes up 60-90% body weight of most organisms. 2. 8: cohesion of water molecules along a surface produces surface tension. Spiders and water striders rely on surface tension to move across the surface of ponds (l- below) Water molecules stick to polar or charged surfaces according to the property called adhesion: adhesion helps water climb up the thin tubes of plants to the leaves. Fats and oils: water-based solutions can be acidic, basic, or neutral. A small fraction of water molecules break apart into ions (fig. Lemon juice and vinegar are naturally occurring acids. A base is a substance that combines with hydrogen ions (reducing their numbers) with hydrogen ions: baking soda, chlorine bleach, and ammonia are basic. The degree of acidity of a solution is measured using the ph scale: ph 0 6 is acidic (h+ > oh , ph 7 is neutral (h+ = oh , ph 8 14 is basic (oh > h+)
