What is a mixture? How are mixtures different from pure substances?

Mixtures are collections of different substances (ingredients) mixed with each other.
Pure substances do not have any impurities of other substances. Pure substances have constant physical properties.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.