Question

Classify the following as element, mixture or compound:

blood

Answer 1

Blood can be classified as a mixture because:

• Blood consists of various types of cells, proteins along with plasma most of which is water.
• The blood cells (white blood cells, red blood cells, etc.) can be separated using the physical method of separation called centrifugation.

Mixture: When two or more substances (elements or compounds or an element and compound) are mixed in any proportion.

• The components of a mixture can be separated by physical methods of separation.
• Example: A mixture of Sand and Iron $\left(\mathrm{Fe}\right)$ can be separated by the use of a magnet (physical process) where Iron gets attracted to the magnet leaving behind the sand.

Element: An element is a pure substance that cannot be split into simpler substances and comprises only one type of atom.

• Example: Hydrogen $\left({\mathrm{H}}_2\right)$, Copper $\left(\mathrm{Cu}\right)$ etc.

Compound: A compound is a pure substance in which elements combine chemically in a fixed composition to give a compound.

• They can be broken down into elements that make up the compound by using chemical or electrochemical methods.
• The properties of the compound are entirely different from the elements from which it is formed.
• Example: Water $\left({\mathrm{H}}_2\mathrm{O}\right)$, Common salt i.e.; Sodium chloride $\left(\mathrm{NaCl}\right)$