I2(aq) + 2S2O32- 2I- + S4O62-(aq) It is then possible to calculate the amount of iodine that reacted with the original fat or oil and the answer called the iodine value is usually expressed as grams iodine/100 grams of fat or oil. The higher the value, the more unsaturated the fat or oil. Melting Points of Fats and Oils The lower melting points of oils compared to those of fats is related to the higher unsaturation of oil molecules. The presence of double bonds in oil molecules causes the long chains of atoms to become distorted. This stops the oil molecules packing as closely together as the more saturated fat molecules can. The poorer packing means less London dispersion forces can form between oil molecules than between fat molecules. Less heat energy is needed to separate oil molecules and oils have lower melting points than fats. Proteins - Glossary Word Meaning Ester Link A group of atoms of formula -COO- found in ester molecules and made from the combination of the carboxyl group and the alcohol group. Condensation A reaction where two or more molecules join Reaction together and a small molecule, usually water is eliminated.
I2(aq) + 2S2O32- 2I- + S4O62-(aq) It is then possible to calculate the amount of iodine that reacted with the original fat or oil and the answer called the iodine value is usually expressed as grams iodine/100 grams of fat or oil. The higher the value, the more unsaturated the fat or oil. Melting Points of Fats and Oils The lower melting points of oils compared to those of fats is related to the higher unsaturation of oil molecules. The presence of double bonds in oil molecules causes the long chains of atoms to become distorted. This stops the oil molecules packing as closely together as the more saturated fat molecules can. The poorer packing means less London dispersion forces can form between oil molecules than between fat molecules. Less heat energy is needed to separate oil molecules and oils have lower melting points than fats. Proteins - Glossary Word Meaning Ester Link A group of atoms of formula -COO- found in ester molecules and made from the combination of the carboxyl group and the alcohol group. Condensation Reaction A reaction where two or more molecules join together and a small molecule, usually water is eliminated.
Esters-Fats-and-Oils-Pupil-Notes.docx