Mixtures, Solubility, and Acid/Base Solutions

Chapter 10.1p 334-340

Substances• A substance is matter that is always made up

of the same combination of atom.• There are 2 types of substances

– Elements*• *Only made up of one atom

– Compounds• A compound is matter made of atoms of 2 or more

elements chemically bonded together

• Because the composition of elements and compounds do not change, all elements and compounds are substances

Mixture

• A mixture is two or more substances that are physically blended but are not chemically bonded together.– *The amount of each substance in a

mixture can vary. (Unlike atoms in a compound)

Mixtures• Granite

– A type of rock– Composition of

different rocks

• Air– Doesn’t look like a

mixture– 78% nitrogen– 21% oxygen– 1% other substances

2 Types of Mixtures

• Heterogeneous Mixture– Heterogeneous = diverse

• Homogeneous Mixture – Solutions– Homogeneous = of the same kind; alike

Heterogeneous Mixture

• A heterogeneous mixture is a mixture in which substances are not even mixed.– Example:

• Granite is a heterogeneous mixture. It is not evenly mixed.

• Often, you can see the different substances and parts of a heterogeneous mixture with unaided eyes, but sometimes you need a microscope.– Example:

• Blood is a heterogeneous mixture. • It looks evenly mixed, but with a microscope you can easily

see areas with more of one component and less of another.

• Heterogeneous mixture can be hard to tell.

Which of the following diagrams shows a heterogeneous mixture?

                                                                                            

                                                 

Solution – Homogeneous Mixtures

• Many mixtures look evenly mixed even when you view them with a powerful microscope.

• These mixtures are homogeneous• A homogeneous mixture is a mixture in

which two or more substances are evenly mixed on the atomic level but not bonded together.– The mixture looks evenly mixed because the

individual atoms and compounds are too small to see

Solution

• *Another name for a homogeneous mixture is a solution.

• Air is a solution. Soda is also a solution.• Heterogeneous mixture can be hard to tell.

How do compounds and mixtures differ?

• There are 2 important differences between compounds and mixtures– Substances in a mixture keep their properties

because they are not chemically changed• Salt water is a mixture. You can’t see the salt, but

you can taste it in the water.• In contrast, sodium and chlorine bond to form table

salt.– Sodium is a soft, opaque, silvery metal– Chlorine is a greenish, poisonous gas– Salt has none of these properties

– Mixtures can be separated• Because substances in mixtures are not

bonded, they can be separated using physical methods

– For example you can boil the water out of salt water

– The physical properties of one substance will differ from the other, so they can be physically separated

• In contrast, compounds can only be separated by chemical change that breaks the bonds between the elements.

– Look at the figure on page 339

Distillation of Salt Water