Question

When an Incense stick has lightened the vapours from it are large enough that they are visible to the naked eye. Does that mean that it forms a heterogeneous mixture with air?

Answer 1

Hint : If the composition is not uniform throughout the whole mixture, then it is called heterogeneous mixture. These types of mixtures consist of two or more phases. The components in a heterogeneous mixture do not mix completely but form two separate layers. Each layer in the mixture is called a phase.

Complete Step By Step Answer:
A heterogeneous mixture has different substances or phases involved. The composition of a heterogeneous mixture varies. These mixtures are classified on the basis of their size into three types: Colloids, suspensions and solutions. The components of a heterogeneous mixture retain their original chemical properties when they are mixed and they can be distinguished even after mixing them. Colloids are a type of heterogeneous mixtures in which the size of a particle is very small to be seen with the naked eye, but the particles are big enough to scatter light. In colloids, the particles are called the dispersed phase and the medium in which they are distributed is called the dispersion medium.

Note :
If the composition is uniform throughout the mixture, then it is called homogeneous mixture. A heterogeneous mixture contains two or more than two phases. The phases may be two solids, liquids or gases or a solid/liquid or liquid/liquid or gas/liquid or gas/solid. These different phases mix together but are physically separate.