Final answer:
Unsaturated fats remain liquid at room temperature due to the presence of double bonds, which create bends in the fatty acid chains and prevent tight packing. This results in a lower melting point compared to saturated fats which have straight chains and are solid at room temperature.
Step-by-step explanation:
An unsaturated fat stays liquid at room temperature due to the presence of double bonds in the fatty acid chains. These double bonds create kinks or bends in the chains which prevent the fat molecules from packing together tightly. This loose structure results in a lower melting point, making unsaturated fats, such as olive oil and canola oil, liquids at room temperature. In contrast, saturated fats lack these double bonds and have straight chains that can pack closely together, leading to higher melting points and solid forms at room temperature.
Notably, trans unsaturated fatty acids, despite having double bonds, are more linear like saturated fatty acids due to the orientation of the hydrogen atoms across the double bond. This linear structure allows them to pack more tightly, often resulting in them being solids at room temperature as well.