Water and Solutions Acids and Bases Nearly 70% of your body is water Functions of Water Water helps body with homeostasis Helps retain body heat Helps cool body Cohesion and Adhesion Cohesion is attraction between substances of the same kind – Water is cohesive – it is attracted to itself Adhesion is attraction between substances of different kinds Water is adhesive – it is attracted to other polar substances Adhesion – allows for capillary action that allows water to move up in the stems of plants Aqueous Solutions Solution – a mixture in which one or more substances are evenly distributed in another Aqueous solution – a mixture in which one or more substances are evenly distributed in water Polarity of water allows many substances to dissolve in it. Acids and Bases Water can disassociate into ions: MORE hydrogen ions = ACID H2O H+ + OH- Water has low number of Hydroxide (OH-) and hydrogen ions (H+) in equal numbers Acids – form H+ in solution Bases – form OH- in solution MORE hydroxide ions = BASE pH Scale Based on concentration of hydrogen ions All solutions have pH between 0 and 14 Pure water pH = 7 Acidic solutions pH less than 7 Basic solutions pH more than 7 Each whole number represents a factor of 10 on pH scale. pH 5 has 10 times more hydrogen ions than pH 6. Common Acids and Bases pH Scale pH Lab Predict pH of various household substances and test using pH paper