Classifying matter

What is matter? Anything that has mass and volume There are 3 states of matter: liquid, solid, and gas

Pure substance Matter that has exactly the same composition Every sample has the same properties Examples: sodium, gold

element A substance that cannot be broken down into simpler substances Has a fixed composition because it only contains one type of atom Examples; hydrogen, oxygen, helium, gold, mercury, nitrogen

Periodic table of elements

compounds Substance that is made of 2 or more simpler substances and can be broken down into those simpler substances. Example: Water H2O , Quartz SiO2 Water has 2 hydrogen atoms and 1 oxygen atom Quartz has 1 silicon atom and 2 oxygen atoms

Are these elements or compounds? FeO2 Ag Ar CO2 NaCl CaCO3 H2

Mixtures Properties of a mixture can vary because the composition of a mixture is not fixed Example: salsa The type of peppers used and quantity of peppers will determine how spicy it is No matter how well you stir a batch of salsa . The ingredients will never be evenly distributed

Heterogeneous mixture Different kind Parts of the mixture are noticeably different Example: sand, salsa

Homogeneous mixture All parts look the same Substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another Appears to contain one substance Example: stainless steel spoon made of a mixture of iron, chromium, and nickel

What type of mixture are these pictures?

Solution Occurs when substances dissolve and form a homogenous mixture Ex: kool aid, tap water with salt

Suspension Heterogeneous mixture that separates into layers over time “shake well before using” Examples: container filled with sand and water

colloids Contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension. They do not separate into layers You can not use a filter to separate. Ex: homogenized milk

Homogenized milk Milk is a mixture of substances including water, sugar, proteins, and fats. When fresh cow’s milk is allowed to stand, a layer of cream rises to the top. This layer contains most of the fat. When you buy milk at the store, the cream does not form a separate layer because the milk has been processed so that the fat remains dispersed throughout the milk, making it a colloid

Fresh cow’s milk unhomogenized Homogenized cow’s milk (colloid)