Classification of Matter

Classification of Matter Pure Substance Elements Compounds Mixtures Heterogeneous Homogeneous Remember that matter is anything that has mass and takes up space. We classify matter two ways. Substances that are then broken down into elements and compounds and Mixtures which are broken into heterogeneous and homogeneous.

(Pure) Substances In a substance, all particles (atoms or molecules) are the same Has a definite composition (always the same ‘recipe’) Has a unique set of molecules Substances is anything made of atoms and molecules. It is classified as a substance it has a defined composition or recipe. A substance is chemically bonded together like water. Water is made of 2 hydrogen and 1 oxygen. It is made that way every time. If you change the recipe you change the substance. For example, water is H2O but if you add an extra oxygen H2O2 it becomes Hydrogen peroxide.

Elements An element is a substance made of atoms May be man-made, or in nature Examples of elements: Neon gas (single Neon atoms) Oxygen gas (two oxygen atoms bonded together) Elements are classified as atoms of a single kind of element. Remember elements are on the periodic table. Like Neon or Oxygen. Notice Oxygen is O2 this is because the oxygen you breathe is two Oxygens bonded together. It is still considered an element because they are both oxygen.

Compounds Compounds are molecules made from combining two elements A compound is a pure substance because all of the molecules are identical, but it is not an element. Example: Water H2O Compounds are anything bonded together but it contains 2 or more kinds of elements. Like water, each water molecule looks exactly the same and contains both hydrogen and oxygen.

Mixtures In a mixture, Two or more substances Composition is not uniform Not chemically bonded Mixtures are not chemically bonded. The composition is not uniform and items can be easily separated. Like a blueberry muffin. You can pick out the blueberries and it’s still a blueberry muffin.

Heterogeneous Mixture Visibly different particles Examples: Dressing has visible bits of seasoning, droplets of oil and water Ocean has water, salt, algae, fine sand particles, living cells Heterogeneous mixture is anything that is visibly different. Like a fruit salad, you can eat the strawberries and then the pineapple. The ocean is heterogeneous because you can see the fish, sharks, whales, and sand. You can pick up the kelp and throw it at your friend and it’s still the ocean.

Homogeneous Mixture All particles of all types present are the same; you cannot separate Example: Sugar dissolved in water Homogeneous is like taking that fruit salad and putting it in the blender and hitting frappe. It’s now a smoothie. So think of heterogeneous like a fruit salad and homogeneous like a smoothie. Homogeneous is visibly the same.

Homogeneous Mixtures are also called ‘Solutions’ Can be a liquid or a gas or a solid A solution may be a compound (such as water) Or a homogeneous mixture Examples: Air, which is made up of oxygen, nitrogen, carbon dioxide, water vapor, and other gases Stainless steel, which is made up of a mixture of metals (iron, chromium, nickel) Homogeneous mixtures can also be called solutions. It can be either a solid, liquid, or a gas. For example, air has oxygen molecules, carbon dioxide molecules, and nitrogen. These substances are not chemically bonded together they simply exist together in air. Stainless steel is an alloy (a mixture of metals) you take iron, chromium, and nickel and melt them down mix them together and when they harden you have stainless steel.