States of Matter - Set #4 PDF

Phase Changes Physical vs. Chemical Change Physica Chemical l http://cwx.prenhall.com/petrucci/chapter1/medialib/tutor/f20/0103.html  Chemical Change A chemical change always results in the formation of a different subst...

Phase Changes Physical vs. Chemical Change Physica Chemical l http://cwx.prenhall.com/petrucci/chapter1/medialib/tutor/f20/0103.html  Chemical Change A chemical change always results in the formation of a different substance or substances.  Physical Properties 2 Categories of Physical Properties: 1) Qualitative Properties ( sensed/ observed) Color Texture Smell Taste Malleability Texture Change in state Ductility  Physical Properties 2) Quantitative Properties (measured) Melting point (mp) Boiling Point (bp) Density  d= m/v (mass/volume) Solubility Viscosity (flow rate) Conductivity  Chemical Reactions Characteristics – Energy change (temperature, light, sound, electricity) – Odor Change (appearance or disappearance) – Color change – Formation of a gas – Formation of a solid (precipitate) http://www.youtube.com/watch?v=66kuhJkQCVM  Test Your Understanding A blue crystal is placed in water and after stirring it disappears and the water becomes blue. The liquid is then heated and the water evaporates and small blue crystals appear. Did a chemical reaction take place? =  Answer NO. The crystal dissolved and then the water evaporated. This was only a phase change not a chemical change. No new substance was created. And Now You Know!  Test Your Understanding If a marshmallow is cooked over a flame and becomes black on the outside, did a chemical reaction occur? Defend your answer =  Answer YES! A new color appears (black crust) and a new substance was produced (carbon crust) Change Physical Chemical Evidence Frying an Egg Boiling Water Leaves changing in the Fall Rusting Iron And One More Time… 1) Color change 2) Gas is formed 3) New odor is formed 4) Precipitate (solid) is formed 5) Temperature rise or drop  Your Task Create a set of notes summarizing the differences between chemical and physical changes/reactions Check & Reflect p 25 # 1,5-8 & 11 Section Review page 27 # 5, 10, 11, 12, 15, 16