Mixtures and Compounds in Chemistry

A series of free High School Chemistry Video Lessons.

In this lesson, we will learn

  • Conservation of Mass
  • Law of Definite Proportions and Law of Multiple Proportions
  • Heterogeneous and Homogeneous Mixtures
  • Elements and Compounds



Conservation of Mass
The law of conservation of mass states that mass is neither created nor destroyed. In a closed system, mass of reactants is equal to mass of products. The law of conservation of mass is related to the law of conservation of matter.

Understanding the law of conservation of mass.

This video demonstrates the Law of Conservation of Mass with an experiment.



Law of Definite Proportions - Law of Multiple Proportions
The law of definite proportions, also known law of definite composition, states that regardless of the amount, a pure compound always contains the same elements in the same proportions by mass. Law of multiple proportions, also known as Dalton’s Law, states that when one element combines with another to form more than one compound, the mass rations of the elements in the compounds are simple whole numbers of each other.

Understanding the laws of definite and multiple proportions.



Law of Definite and Multiple Proportions
Based on The Law of Conservation of Mass



Mixtures are composed of pure substances and elements, but unlike compounds these substances retain their own chemical identities and properties. Mixtures can be homogeneous or heterogeneous. Homogeneous mixtures are the same throughout and are called solutions. Heterogeneous mixtures don’t have uniform composition.

The properties of homogeneous and heterogeneous mixtures.



Heterogeneous and Homogeneous Mixtures



Elements and Compounds
Elements and compounds are differentiated by their composition. Elements cannot be decomposed into simpler substances. Compounds are composed of two or more elements, but the chemical identities and properties of these elements change when they form a compound. Mixtures on the other hand are composed of elements which retain their chemical identities.

The differences between elements and compounds.



Elements and Compounds




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