BENG 130 Lecture 9: Lecture 09
Document Summary
Lecture 09: given variables (like v, t, p, etc. If, at a given p, t, v, etc. , the system is liquid, that means liquid is the most stable phase at those conditions. Constant pressure and temperature: =(cid:1833)(cid:3040)=(cid:4672)(cid:3008)(cid:3041)(cid:4673),(cid:3021, = (cid:1845)(cid:3040)(cid:1846)+(cid:3040, (cid:4672)(cid:3021)(cid:4673)= (cid:1845)(cid:3040, (cid:4672)(cid:4673)(cid:3021)=(cid:3040, recall that (cid:1845)(cid:3040) and (cid:3040) are always positive. Thus, as p increases, increases: for going from solid to liquid or liquid to gas, the system has to absorb heat, so. Thus, if we plot against t for every phase: This graph assumes constant pressure: if you increase pressure, you shift all 3 curves right, so the freezing/melting and the condensing/boiling temperatures both increase (the intersections of the lines are shifted right on the t axis) Phase diagram: for almost all elements, the line between solid and liquid has positive slope. For water, it has a negative slope, which is vital for life. Because of this, ice is less dense than liquid water, so ice floats.
