Saturated vs Unsaturated – Alkenes and Alkanes – Fats and Oils


The test for Alkanes and Alkenes is Bromine water:

Alkanes have single bonds makes the already yellow bromine water stay yellow.

In comparison…

Alkenes have double bonds and make the yellow bromine water turn colourless (don’t say see-through)

Fats and Oils
The more viscous a substance is, the more saturated fats they have, and the less saturated.

Viscosity is a measure of how well a substance flows.
Mono saturates have one double bond
Poly saturates have more than one double bond

Saturated fats
These fats are straight – this means they line up well so there is more friction between the molecules – so they are viscous or solid.
Mono unsaturated fats
These fats contain a bend – this means they don’t like up well so there is less friction between the molecules so they are not viscous or a liquid.


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