A laboratory reports the following vapor-pressure (P sat) data for a particular

Question

A laboratory reports the following vapor-pressure (P sat) data for a particular organic chemical t/oC AP Sat t/oC P sat/kPa 18.5 3.18 32.7 41.9 9.5 5.48 44.4 66.6 0.2 9.45 52.1 89.5 11.8 16.9 63.3 129 23.1 28.2 75.5 187 Correlate the data by fitting them to the Antoine equation In P Sat A T/K C That is, find numerical values of parameters A, B, and C by an appropriate regression procedure. Discuss the comparison of correlated with experimental values. What is the predicted normal boiling point of this chemical?

Explanation / Answer

given lnP= A-(B/T+C)

Multiplying with T+C gives

lnP*(T+C)= A*(T+C)- B

TlnP+C lnP= AT+AC-B

TlnP= AT +AC-B-ClnP

lnP= A + (AC-B)/T- C lnP/T

lnP= A + A1x1-CX2 where X1=1/T and X2= lnP/T, A1= (AC-B)

this is a multiple linear regression and the calculations linset functinos in excel will be used for calculations for determining A , A1 and C

The plot is shown below along with the calculations along withe predicted vapor pressure

Antoine constants are A = 13.821, B = 2518.726 and C = 217.3944

lnP= 13.821- 2518.726/ (217.3944 +T)

at boilng point P= 101.3 Kpa

ln 101.3 =13.821- 2518.726/ (217.3944+T)

4.62= 13.821- 2518.726/ (T+ 217.3944)

2518.726/ (T+217.3944)= 13.821-4.62=9.201

T+ 217.3944= 2518.726/9.201=273.74

T= 56.35 deg.c

Experimental Vapor pressure data of a Chemical Pressure Pressure Temp. Kpa y x1 x2 Fitted Deg C ln (P) 1/T ln(P)/T mm Hg -18.5 3.18 1.16 -0.054 -0.063 3.2 -9.5 5.48 1.70 -0.105 -0.179 5.5 0.2 9.45 2.25 5.000 11.230 9.4 11.8 16.9 2.83 0.085 0.240 17.0 23.1 28.2 3.34 0.043 0.145 28.5 32.7 41.9 3.74 0.031 0.114 42.5 44.4 66.6 4.20 0.023 0.095 66.7 52.1 89.5 4.49 0.019 0.086 87.8 63.3 129 4.86 0.016 0.077 127.5 75.5 187 5.23 0.013 0.069 185.3

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.