Name _____________________________ Date _______________ Mixtures Reading Mixtures Matter that consists of two or more substances that are not chemically combined is called a mixture. Mixtures are classified according to how well they are mixed. Heterogeneous mixtures are the least mixed. The particles of this mixture are large enough to be seen and to separate. The particles will settle out on standing. An example of this mixture would be sand and water. Homogeneous mixtures are well mixed. The particles that make up this mixture are very small and do not settle out when allowed to stand. Solutions and colloids are examples of homogeneous mixtures. Solutions A solution is a mixture of one substance dissolved in another so the properties are the same throughout. A solution is composed of a solute and the solvent. The solute is the substance being dissolved and the solvent is the part of the solution that does the dissolving. The solute is of molecular size. Below are some examples of solutions Suspensions A ​
suspension​
is a mixture between two substances, one of which is finely divided and dispersed in the other. Common suspensions include sand in water, dust in air, and droplets of oil in air. Particles in a suspension are larger than those in a solutions; they are visible under a microscope and can often be seen with the naked eye. Particles in a suspension will settle out if the suspension is allowed to stand undisturbed. Many particles of a suspension can be separated through a filter. An example of a simple suspension would be flour in water, or sand in water. Colloids A colloid is a type of mixture intermediate between a ​
homogeneous mixture (​
also called a solution​
)​
and a ​
heterogeneous mixture​
with properties also intermediate between the two. The particles in a colloid can be solid, liquid or bubbles of gas. The medium that they are suspended in can be a solid, liquid or gas (although gas colloids cannot be suspended in gas).The particles are approximately 10 to 10,000 angstroms in size and generally cannot be filtered, or settled out in an easy manner. Colloids may be colored or translucent because of 1 Name _____________________________ Date _______________ Mixtures Reading the Tyndall effect, which is the scattering of light by particles in the colloid. Colloid particles may be seen in a beam of light such as dust in air in a "shaft" of sunlight.1 Questions What factor distinguishes a suspension from a colloid? Why were the iron filings in water a suspension? Explain. Why was the ferrofluid a colloid? Explain. Give an example of something that would be a colloid that is not on the list of examples above. 1
"Suspensions, Emulsions and Colloids ­ Edinformatics." 2006. 11 Jun. 2014 <​
http://www.edinformatics.com/math_science/suspensions_colloids.htm​
> 2 Name _____________________________ Date _______________ Mixtures Reading 3