6th Grade Life Science Miss Sauer COMPOUNDS 6th Grade Life Science Miss Sauer

MATTER Matter: is everything that takes up space and has mass.

MATTER The three forms of matter are: Solid, Liquid, and Gas. There is a 4th state of matter (plasma), but we will just be talking about the 3 states of matter in this class.

Solids: A solid keeps its shape and has a certain volume.

Liquids: A liquid doesn’t have a certain shape of its own. A liquid takes the shape of its container.

Gases: A gas doesn’t have a certain shape or a certain volume.

Lesson 2: What Is a Compound? Matter can be classified as either: a pure substance a mixture

PURE SUBSTANCE A pure substance can be an element or a compound. Compounds are held together by chemical bonds. Pure substance: always has the same composition and properties.

Example of a Pure Substance: Example of a pure substance: carbon dioxide.

Types of PURE SUBSTANCES: Two types of Pure Substances: Elements Compounds

ELEMENTS Element: is a substance that cannot be broken down into other substances.

Properties of Elements: Elements consist of only one kind of atom.

What is an ELEMENT? A substance composed of a single kind of atom. Cannot be broken down into another substance by chemical or physical means.

COMPOUNDS: Compound: a pure substance made up of two or more elements that are chemically combined. Example: carbon dioxide (made up of the elements of carbon and oxygen)

Properties of a Compound: Properties of a compound are usually different from the properties of the elements that make it up.

What is a COMPOUND? A substance in which two or more different elements are CHEMICALLY bonded together.

Classification of Matter: All matter can be classified as either a pure substance or a mixture. Remember: Matter can be classified as either: a pure substance a mixture

PURE SUBSTANCE: Pure Substance: has definite composition and the same composition and properties regardless of where it comes from. Has uniform composition throughout.

MIXTURE Mixture: made up of 2 or more substances that are NOT chemically combined. Each substance keeps its original properties (whether we are adding them or taking them out).

MIXTURE Mixture: has a variable makeup. Mixtures can be: Evenly mixed Unevenly mixed

Formation of a Compound: The formation of a compound involves a chemical change. During the chemical change, bonds form between the atoms of the elements that make up the new compound.

Chemical Bonds: Chemical Bond: a force attraction between atoms or ions. (HOLDS IT TOGETHER!) Once a compound forms, only another chemical change breaks the bonds.

Chemical Bonds (continued): Atoms form chemical bonds because certain arrangements of their electrons are more stable than others. (Remember: on the periodic table, elements in a group have similar electron arrangements and thus, similar kinds of bonds)

Chemical Bonds (continued): The transfer or sharing of electrons forms bonds between atoms.

Chemical Bonds (continued): Two Types of Bonds: Covalent bonds Ionic bonds

Covalent Bonds: Covalent bonds: form when two atoms share their outermost electrons.

The co-captains share responsibilities. Covalent Bonds: Think of co-captains on a team… OR Think of co-captains on a plane… The co-captains share responsibilities.

MOLECULE: Molecule: A group of two or more atoms held together by covalent bonds. Example: methane gas

IONIC BOND: Ionic bond: form when one or more electrons are removed from one atom and attach to another atom.

Difference between Covalent & Ionic Bonds: Covalent Bond: Formed when two atoms SHARE their outermost electrons. Ionic Bond: Formed when one or more electrons are removed from one atom and attach to another atom.

IONS: Remember: Ions are when an atom has more or fewer electrons than it has protons is called an ion. The atom that gives up electrons forms a positive ion. The atom that receives the electrons forms a negative ion. The resulting positive and negative ions attract each other, forming a bond.

Carbon: Carbon forms more compounds than any other element, except Hydrogen

HYDROCARBONS: An important group of carbon compounds are the hydrocarbons. Oil, natural gas, and other fuels are important sources of hydrocarbons. Hydrocarbons are made up of hydrogen and carbon. Gasoline is a mixture of hydrocarbons. When gasoline burns, the hydrocarbons break up and release energy. This energy is used to make the car engine run.

HYDROCARBONS:

POLYMERS: Polymers are long chain-like molecules that may contain hundreds of thousands of carbon atoms, as well as other elements.

CARBOHYDRATES: Many carbon compounds are important to living things, such as carbohydrates. Carbohydrates are made up of carbon, hydrogen, and oxygen. Sugars, starch, and cellulose are some examples. When they break down in the body, they provide energy.

Closure Questions What are the two types of pure substances? What is a compound? What is a mixture? Can mixtures be evenly mixed or unevenly mixed? What is a chemical bond? What is a covalent bond? What is a molecule What is an ionic bond?