2.2 The physical properties of fatty acids are mainly determined by the length and degree of unsaturation on the hydrocarbon chain 2.2. I The shorter the hydrocarbon chain. the lower its melting point(saturated fatty acids of 10 or less carbon atoms are liquid, of 12 or more carbons are waxy or solid at room temperature). 2. 2. 2 Existence of carbon-carbon double bonds lowers the melting point of fatty acids due to the kink introduced by double bonds (therefore preventing the tight packing).2.2 The physical properties of fatty acids are mainly determined by the length and degree of unsaturation on the hydrocarbon chain. 2.2.1 The shorter the hydrocarbon chain, the lower its melting point (saturated fatty acids of 10 or less carbon atoms are liquid, of 12 or more carbons are waxy or solid at room temperature). 2.2.2 Existence of carbon-carbon double bonds lowers the melting point of fatty acids due to the kink introduced by double bonds (therefore preventing the tight packing)