Example 16.3-1 Mass Diffusivity at Low Density
> restart;
> eq := p*DAB/((pcA*pcB)^(1/3)*(TcA*TcB)^(5/12)*(1/MA+1/MB)^(1/2))=a*(T/sqrt(TcA*TcB))^b; eq 16-3.1
> MA:= 39.94*g/mol: TcA:=151.2*K: pcA:=48*atm: properties of argon
> MB:= 32.00*g/mol: TcB:=154.4*K: pcB:=49.7*atm: properties of oxygen
> T:= 293.2*K: p:=1*atm: temp and pressure
> a:=2.745e-4: b:=1.823: constants for the nonpolar pair
> eq;
> assume(atm>0,K>0,mol>0,g>0);
> solve(eq,DAB); solve for DAB
> DABu:=simplify(%);
> DAB:=.1886791089*cm^2/s; The same numeric value but the correct units.
> aun:=DAB/DABu;
> a:=a*aun;
> DAB:='DAB';
> solve(eq,DAB);
> simplify(%);
>