BIOL 1201 Lecture : Lecture 4
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Readings: pgs 46-63 in campbell biology 9th ed. Mastering biology: on-line homework 1, 2 (due 10 am, before class) 95% h2o: solvent for biological reactions, 71% of earths surface is covered by h2o. Solutions a homogeneous mixture consisting of a solvent, and solute(s). Water is an excellent solvent for ionic(positive) or polar molecules(positive and negative regions) (see figs. Concentration = mass (weight)/volume: in reactions, molecules combine by number, a mole of any compound possesses 6. 02 x1023 molecules, molarity (concentration) moles per liter of solution (mol/l) Mole (mol) - sum of the atomic weights (mass numbers) in daltons (= grams) Calculating molarity - molar concentration (mol / l) 17. 4g x 1mol/58g=0. 3mol: divide moles of nacl in solution volume (l) 17. 4g of nacl dissolved in 500ml of h2o gives a concentration of 0. 6m. Hydronium ion hydronide ion one in every 554 million h2o molecules undergoes a dissociation(p. 52: h2o can dissociate.
