Question

A biologist has crushed flowers and created an extract of plant materials in ethyl alcohol. The mixture contains pigments such as chlorophyll A and B, carotene, and xanthophylls. In your own words, explain how this extract meets the definition of a chemical mixture. Is this mixture homogeneous or heterogeneous? How do you know? How can we separate the plant pigments from one another?

Answer 1

A chemical mixture is defined as the combination of two or more substances and dispersed among each other (mixed together).

The extract meets the definition of the chemical mixture as the extract is the combination of crushed flowers and ethyl alcohol.

The mixture is heterogeneous because crushed flowers and ethyl alcohol vary in proportion and crushed flowers will be visible in the mixture or not uniformly mixed, unlike homogeneous mixtures.

The plant pigments can be separated from one another using a technique called paper chromatography. In this technique, the extract containing the pigments is marked in a paper and is placed in a specified solvent. The solvent starts moving up the paper through capillary action and the pigments start getting visible with different rates because they are not equally soluble.