《物理化学 Physical Chemistry》课程教学资源（英文版）The Properties of Gases

Definition of physical chemistry Physical chemistry stands in the same relation to the subdivisions of chemistry in which philosophy stands toward all the sciences. Its main object is to unify thought within the science of chemistry; therefore, it might well be named, the "philosophy of chemistry'-SLBigelow, 1912

Definition of Physical Chemistry Physical chemistry stands in the same relation to the subdivisions of chemistry in which philosophy stands toward all the sciences. Its main object is to unify thought within the science of chemistry; therefore, it might well be named, the “philosophy of chemistry” - S.L. Bigelow, 1912

The Properties of gases Equations of State o Stephen L. davis. 2003

The Properties of Gases Equations of State © Stephen L. Davis, 2003

Bulk variables Volume-m Pressure pa Temperature-K Composition- moles

Bulk Variables • Volume - m3 • Pressure - Pa • Temperature - K • Composition - moles

Volume length3 unItS m or cm- 1 m liter= 1000 cm3 molar volume V=V/n

Volume • length3 • units – m3 or cm3 – liter = 1000 cm3 • molar volume Vm= V/n 1 m 1 m 1 m

Pressure Force/Area unItS Pascal= newton/m2= joule/m atmosphere=101325 Pa bar= 100000 Pa mm hs g torr

Pressure • Force/Area • units – Pascal = Newton/m2 = Joule/m3 – atmosphere = 101325 Pa – bar = 100000 Pa – mm Hg – torr h

Temperature · thermometry T Volume · only for an ideal gas or real gases in the low pressure limit

Temperature • thermometry T ~ Volume • only for an ideal gas • or real gases in the low pressure limit

Composition moles: n ∑n:=n mole fraction:X ∑x;=1 partial pressure: pi Pi=p

Composition • moles: ni S ni = n • mole fraction: xi S xi = 1 • partial pressure: pi S pi = p

Equations of state PVT and n are not independent Any three will determine the fourth An equation of state is an equation that relates P vT, and n for a given substance Gases have the simplest equations of state The simplest equation of state is the ideal gas law, pv=nrT

Equations of State • P,V,T, and n are not independent. • Any three will determine the fourth. • An equation of state is an equation that relates P,V,T, and n for a given substance. • Gases have the simplest equations of state. • The simplest equation of state is the ideal gas law, pV = nRT

Ideal gas law pV=nRt p≡ pressure V=volume n= moles ·T≡ temperature R=universal gas contant =0.08206 L-atm/mol-K

Ideal Gas Law • p = pressure • V = volume • n = moles • T = temperature • R = universal gas contant = 0.08206 L-atm/mol-K pV = nRT

Partial pressure PAV=nART pa partial pressure of gas A V=total volume na= moles of gas a ·T≡ temperature R=universal gas contant =0.08206 L-atm/mol-K

Partial Pressure • pA = partial pressure of gas A • V = total volume • nA = moles of gas A • T = temperature • R = universal gas contant = 0.08206 L-atm/mol-K pA V = nA RT