Classification of matter essay
“Science ... is organized common sense.” Josepsech Alexander Leighton. Just like Leighton said, science is common sense; so too is the classification of matter. The smallest building block of the classification of matter is, simply, matter. Matter is any substance or material comprised of molecules and atoms. The classification of matter places matter into different categories including elements, compounds, substances, and mixtures, based on its physical and chemical properties.
The simplest classification of matter is an element. An element is a substance that is composed of one single type of atom that cannot be broken down. Elements are organized on the periodic table and are characterized specifically by their unique atomic number. People come across elements everyday, from the Gold and Silver in our jewelry to the Nitrogen and Oxygen we breathe. There are 118 known elements on the periodic table today, starting with Hydrogen and ending with Ununoctium. A more complex category in the classification of matter is compounds. A compound is a substance that consists of more than one type of atom chemically bonded together. In a compound every molecule is the same and can only be separated chemically. Compounds are made up of elements. For example, table salt is Sodium and Chloride and water is Hydrogen and Oxygen. What distinguishes compounds from elements is that elements cannot be separated but compounds can. Because of the unlimited combinations of elements, compounds cannot be classified on a simple table like elements. When doing the classification of matter POGIL, I learned that both compounds and elements are pure substances because their composite particles are identical. In the ‘separating-a-mixture’ lab, I worked with my group to separate Iron, salt and sand. This experiment allowed us to appreciate that Iron is a single element while salt is a compound and sand is a mixture.
Just as an element is a simple category in the classification of matter and a compound is more complex, a pure substance is simpler than a mixture. A pure substance is a form of matter with uniform molecules. Elements and compounds are pure substances but elements are in their simplest state and compounds can be chemically broken down into their separate components. In contrast, a mixture is formed when more than one type of matter is mixed together. Mixtures can be composed of pure substances and can be separated chemically or physically. Mixtures are described as either heterogeneous or homogeneous. A homogeneous mixture looks the same throughout whereas a heterogeneous has visible differences. For instance, chocolate ice cream is a homogeneous mixture whereas chocolate chip ice cream is a heterogeneous mixture. In class we observed the distillation of cherry coke. This demonstration showed us how the heterogenous mixture of cherry coke was separated into water, carbon dioxide, and flavoring. We also learned about the method of chromatography which separates mixtures using water and chromatographic paper.
Simple and Complex categories of matter are described using physical and chemical properties. Physical properties can be classified either qualitatively or quantitatively while chemical properties describe how substances react with other atoms or molecules to produce new substances with different properties. Qualitative physical properties are those that can be visually observed about a substance. Shape, texture, color, and state are examples of physical properties. Unlike qualitative physical properties, quantitative physical properties deal with numbers and are labeled as intensive or extensive. An intensive property such as density or boiling point is the same regardless of quantity. In contrast, an extensive property such as volume or mass does change with quantity. As opposed to the physical properties of matter, the chemical properties of matter detail reactions with other particles that produce new substances with different properties. Reactivity to acid, pH, and heat of combustion are chemical properties. Physical and chemical changes are used to accurately observe properties of a substance in a lab. A physical change as it relates to matter does not change the structure of atoms or molecules; it only affects physical properties. Melting, freezing, condensing, and dissolving in water are all physical changes. A reaction to a substance that produces a new substance with unique chemical properties is a chemical change. Burning, oxidizing, or reacting with acid are all chemical changes. Chemical changes may or may not be reversible. One way to tell if there has been a chemical change is to look for a the formation of a precipitate, a color change, a change in temperature, or a production of a gas. During the Evidence of Chemical Change Lab and The Iron and Sulfur Lab our class observed drastic chemical changes that alter both the appearance and properties of a substance.
In conclusion, science categorizes matter many different ways; into substances, elements, compounds, and mixtures while describing it as having chemical or physical properties, but from the copper pennies in your wallet to the gold ring on your finger, ‘matter’ will always ‘matter.’