Example Calculation
Acetone (Propanone) is the simplest ketone and is separated into three groups in the Joback method: two methyl groups (-CH3) and one ketone group (C=O). Since the methyl group is present twice, its contributions have to be added twice.
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| Property | No. of groups | Group value | No. of groups | Group value | Estimated Value | Unit | |
| Tc | 2 | 0.0141 | 1 | 0.0380 | 0.0662 | 500.5590 | K |
| Pc | 2 | −1.20E−03 | 1 | 3.10E−03 | 7.00E−04 | 48.0250 | bar |
| Vc | 2 | 65.0000 | 1 | 62.0000 | 192.0000 | 209.5000 | cm3/mol |
| Tb | 2 | 23.5800 | 1 | 76.7500 | 123.9100 | 322.1100 | K |
| Tm | 2 | −5.1000 | 1 | 61.2000 | 51.0000 | 173.5000 | K |
| Hformation | 2 | −76.4500 | 1 | −133.2200 | −286.1200 | −217.8300 | kJ/mol |
| Gformation | 2 | −43.9600 | 1 | −120.5000 | −208.4200 | −154.5400 | kJ/mol |
| Cpa | 2 | 1.95E+01 | 1 | 6.45E+00 | 4.55E+01 | ||
| Cpb | 2 | −8.08E−03 | 1 | 6.70E−02 | 5.08E−02 | ||
| Cpc | 2 | 1.53E−04 | 1 | −3.57E−05 | 2.70E−04 | ||
| Cpd | 2 | −9.67E−08 | 1 | 2.86E−09 | −1.91E−07 | ||
| Cp | at T=300 K | 75.3264 | J/(mol*K) | ||||
| Hfusion | 2 | 0.9080 | 1 | 4.1890 | 6.0050 | 5.1250 | kJ/mol |
| Hvap | 2 | 2.3730 | 1 | 8.9720 | 13.7180 | 29.018 | kJ/mol |
| ηa | 2 | 548.2900 | 1 | 340.3500 | 1436.9300 | ||
| ηb | 2 | −1.7190 | 1 | −0.3500 | −3.7880 | ||
| η | at T=300 K | 0.0002942 | Pa s | ||||
Read more about this topic: Joback Method
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