ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: thatdumbstudent on February 23, 2020, 02:21:46 pm
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how does the level of saturation in the starting materials of biodiesel and petrodiesel affect its properties?
are they referring to the double carbon bonds and stuff ? i am lost
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I’m not sure how it affects it. But petrodeisel has saturated hydrocarbons as the carbon is single boded so can make 4/4 bonds hence the term “saturated”. Biodiesel containing the polar Ester group has unsaturated hydrocarbons as they have that double bond between the o and c. This means that carbon will make 3 out of 4 bonds (as in of those is double bonded so it still has 4 but not to 4 different elements) and is “unsaturated”.
And well I guess since double bonds require more energy to overcome:
Biodiesel is more viscous as it has stronger bonds which require more energy to overcome hence its resistance to flow. Petrodiesel has weak dispersion forced between its molecules which require less.
Biodiesel is more dense than petrodiesel as the stronger bonds mean it can compress its self more tightly.
Biodiesel has a high cloud point. (Idk why) which means it’s functionality in lower temps is worse than petrodiesel.
Mod Edit: removed the duplicate post
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Biodiesel has a high cloud point. (Idk why) which means it’s functionality in lower temps is worse than petrodiesel.
Biodiesel has a high cloud point because of its polar group. The cloud point is the temperature at which a substance crystallises. The polar ester group in biodiesel enables it to form stronger intermolecular forces than petrodiesel, attracting molecules more easily and therefore making biodiesel clog up faster as it starts to become more viscous at higher temperatures.