CHEM 123N Lecture Notes - Lecture 10: Reaction Rate, Colloid, Reaction Mechanism

• School: Old Dominion University
• Department: Chemistry And Biochemistry
• Course: CHEM 123N
• Professor: John Donat

Document Summary

Isotonic - same osmotic pressure, solvent passes membrane at the same rate both ways. Hypotonic - lower osmotic pressure, solvent leaves the solution. Particles lar(cid:258)er tha(cid:296) i(cid:296)di(cid:376)idual io(cid:296)s or (cid:295)olecules, but they re too s(cid:295)all to settle out by gravity. Area of chemistry focusing on reaction rates / reaction speed, and on the molecular-le(cid:376)el (cid:376)ie(cid:377) o(cid:257) the path (cid:257)ro(cid:295) reacta(cid:296)ts to products(cid:706)(cid:718)reactio(cid:296) (cid:295)echa(cid:296)is(cid:295)(cid:719)(cid:707). When reactants collide more readily, they react more rapidly. Homogeneous - reactants in the same phase, faster reactions. Heterogeneous - reactants in different phases, limited by reactant contact area, reactions involving solids are faster if surface area is increased. Increasing the concentration of the reactant will generally increase the reaction rate, as more molecules = more collisions. Catalysts affect the reaction rate without being consumed, affect different kinds of collisions and change the mechanism [individual reaction steps in path from reactants to products], which are critical in many biological reactions.