Atoms, elements, mulecules, compounds and mixtures Select a lesson

Atoms, elements, molecules, compounds, substances and mixtures
What is an element
what are chemical coumpounds
What are chemical substances
Types of mixturesSeparation of mixtures
Chemical formulae
Important matter terminology


Asexual Reproduction
Charact' of Living Things

Needs of Living Things
Nutrients in Food
Rock Cycle
States of Matter
The Five Senses
Water Cycle

What is a Mixture

A mixture is formed of little bits of one or more substances mixed together. Usually, the parts can be separated from each other by physical means, because it does not involve any chemical reactions or bonds.

Types of Mixtures
A mixture can involve two or more substances of the same phase or different phases. For example you can mix water and sand (liquid and solid), sugar and salt (solid and solid), water and oil (liquid and liquid) or nitrogen and oxygen (gas and gas). Clearly, mixtures can vary a lot and can be homogeneous or heterogeneous.

Homogeneous mixture:
Mixtures involve mixing substances, so let us first be clear what a homogenous substance is. When a sample of matter has the same composition throughout, we call that substance a homogeneous substance. A cup of water will have the same chemical composition throughout (symbol for water). That makes it a homogeneous substance. A piece of gold will also have the same chemical composition, making it a homogenous substance. Homogeneous Mixtures behave in a similar way — the substance formed appear to have the same chemical composition. Alloys and Solutions are Homogeneous mixtures.
Click on each to find out more:

what are alloys what are solutions mixtures

Heterogeneous Mixture
A mixture can also result in two or more phases clearly separated by boundaries. Very often, the separation can be clearly seen by the eye. A heterogeneous mixture is one that does not have uniform properties and composition. Take a look at a bowl of cereal with nuts. A spoon full will surely have a different number of nuts than a second spoonful taken at random. Another example—take some sea-sand into your palms. Look at it closely and you will notice that some sand particles are bigger than others, and the colors of some particles may be different too. They are NOT uniform in any way!
Heterogeneous mixtures include colloids, emulsions or suspensions.
Click on each to find out more:

what are suspensions What are emulsions What are colloids

Click on the above heterogeneous mixtures to learn more about them.

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ubstances and molecules