Which represents a mixture

There are significant differences in properties between pure substances and mixtures. In a pure substance the atoms are usually strongly bonded together to form an element or compound molecule and all the 'particles' are identical. In a mixture there are at least two different particles, i. Model 1. In particle pictures, a pure substance will be represented by a single type of particle, either a single circle for one atom element or several atoms joined together to form a molecule element or compound.

In a particle picture of a mixture, there will be at least two different types of particles, which can be elements single atoms or larger molecules of two or more atoms or compounds molecules of two or more atoms of different elements combined together. Pure substances melt and boil at a fixed temperature; their composition is fixed, i. Mixtures take the form of alloys, solutions, suspensions, and colloids.

A heterogeneous mixture is a mixture of two or more chemical substances elements or compounds , where the different components can be visually distinguished and easily separated by physical means. Examples include:. A homogeneous mixture is a mixture of two or more chemical substances elements or compounds , where the different components cannot be visually distinguished.

The composition of homogeneous mixtures is constant. Often separating the components of a homogeneous mixture is more challenging than separating the components of a heterogeneous mixture. Distinguishing between homogeneous and heterogeneous mixtures is a matter of the scale of sampling. On a small enough scale, any mixture can be said to be heterogeneous, because a sample could be as small as a single molecule. In practical terms, if the property of interest is the same regardless of how much of the mixture is taken, the mixture is homogeneous.

Some mixtures can be separated into their components by physical mechanical or thermal means. Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:. Skip to main content. Introduction to Chemistry. Search for:. Substances and Mixtures. Learning Objective Distinguish chemical substances from mixtures. Key Points Matter can be broken down into two categories: pure substances and mixtures.

Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule. A mixture is composed of different types of atoms or molecules that are not chemically bonded. A heterogeneous mixture is a mixture of two or more chemical substances where the various components can be visually distinguished.

A homogeneous mixture is a type of mixture in which the composition is uniform and every part of the solution has the same properties.