Elements, Compounds, and Mixtures

3 KINDS OF MATTER Elements Compounds Mixtures

IQ3/24/14 What is the chemical formula for water? What are the elements that make up water?

Elements Element: a basic substance made of one type of atom that cannot be separated into a simpler substance Each element is made up of the same type of atoms.(based on number of protons)

Compounds A compound is a substance made of two or more different kinds of elements chemically combined in a specific ratio. Each compound has a formula with symbols to identify the elements in it. formula shows the ratio of elements in the compound. H 2 O – ratio of Hydrogen is 2:1 Oxygen

The subscript lets us know how many atoms are present. The coefficient lets us know how many molecules are present.

Compounds

NaCl is the formula for salt

Water is H 2 O An oxygen atom can bond with two hydrogen atoms to make a molecule we call water. Water is an example of a compound, because it contains more than one kind of atom. The formula for water is H2O, meaning there are two hydrogen atoms for each oxygen atom.oxygenatombondhydrogenmolecule

Carbon Dioxide CO 2 Carbon dioxide molecules are made from one carbon and two oxygen atoms joined together by covalent bonds. The chemical symbol is CO2.

Glucose - C 6 H 12 O 6

Molecules A molecule is formed when two or more atoms join together chemically. atoms Diatomic molecules are made of two atoms of the same element. Hydrogen – H 2 Oxygen – O 2

What is the difference between a compound and a molecule? A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains at least two different elements. All compounds are molecules but not all molecules are compounds.

Molecular hydrogen (H 2 ), molecular oxygen (O 2 ) and molecular nitrogen (N 2 ) are not compounds because each is composed of a single element.hydrogen oxygennitrogen Water (H 2 O), carbon dioxide (CO 2 ) and methane (CH 4 ) are compounds because each is made from more than one element.

Molecule The smallest bit of each of these substances would be referred to as a molecule. For example, a single molecule of molecular hydrogen is made from two atoms of hydrogen. A single molecule of water is made from two atoms of hydrogen and one atom of oxygen.

IQ3/25/14 What is a mixture? Give 3 examples of mixtures.

Mixtures A mixture is made from two or more substances either elements, compounds or both - that are not chemically combined.

Substances in a mixture keep their individual properties. Mixtures are not necessarily present in specific ratios.

Heterogeneous Mixture A mixture in which different materials can be easily distinguished (seen). Ex. Pizza, soup, chex mix, trail mix, Italian salad dressing, snow globe

Solutions Homogeneous mixture/SOLUTION: a substance in which two or more substances are uniformly spread out. Ex.salt water.

Solutions Solute substance being dissolved. Solvent substance that dissolves a solute. Solubility amount of a substance (solute) that will dissolve in a solvent. Salt water: Water: solvent NaCl: solute

IQ4/8/14 Give an example of a solution. What are the substances that make up the solution? Identify the solute and the solvent.

Colloids Heterogeneous mixture that never settles. Particles remain spread out, but are larger than the particles in a solution Ex. Milk, jello, margarine

suspension A suspension is a heterogeneous mixture containing a liquid in which visible particles settle. ex.River water Snow globe Italian dressing

Molecule When a compound is broken down into its’ smallest piece it is called a molecule. You should be able to write the formula for the following: Water Oxygen Carbon Dioxide

DNA Is a large molecule made up of carbon, hydrogen, nitrogen, oxygen, and phosphorous.

Compounds and Mixtures Most of the matter around you is in the form of compounds or mixtures. Water, carbon dioxide, salt, vinegar, baking soda, lye, sugar, gasoline, and bleach are all chemical compounds.

Kinetic theory of matter The idea that all matter is made up of constantly moving tiny particles.

Elements form compounds to try to fill their outer energy level with valence electrons. This is called chemically stable. If the atom is not chemically stable it will lose, share, or gain electrons. A chemical bond is the force that holds together the atoms in a substance.

Forming an Ionic Bond:. Sodium has one valence electron and transfers that electron to chlorine Na + Cl- the negative and positive electrical charges attract each other so the oppositely charged ions come together and form sodium chloride (salt).

An ionic bond is the attraction between two oppositely charged ions. This attraction is similar to the attraction between opposite poles of two magnets..

When two ions come together the opposite charges cancel out. Compounds are electrically neutral. When the ions come together they do so in a way that balances out the charges on the ions

Molecules and Covalent Bonds The attraction that forms between atoms when they share electrons is known as a covalent bond.