Aim: How do we classify matter? 1) Two grams of potassium chloride are completely dissolved in a sample of water in a beaker. This solution is classified as A) an element B) a compound C) a homogeneous mixture D) a heterogeneous mixture 2Which formula represents a mixture? A) C6H12O6(l) B) C6H12O6(s) C) LiCl(aq) D) LiCl(s) Warm Up:

Classifying Matter Pure Substance: contains only one type of matter. Ex: pure water Mixture: contains two or more types of matter. Ex: pool water (contains water and chlorine)

Pure Substances 1. Elements: one type of atom that cannot be broken down by chemical means. 2. Compounds: two or more different types of atoms bonded together that can be broken down by chemical means.

Element or Compound? element element compound

Elements Can be either atoms or molecules. All elements are located on the Periodic Table of Elements. Examples of elements that are atoms: Na, K, S, C, Au, Ag, Kr, etc. Examples of elements that are molecules: O2, H2, Cl2, N2 ** Please note that both only contain one type of atom!

The elements that are molecules are called diatomic elements. How am I supposed to know which elements are atoms and which are molecules?? That’s easy! The elements that are molecules are called diatomic elements. You need to memorize the words H O F Br I N Cl Hydrogen (H2) Bromine (Br2) Oxygen (O2) Iodine (I2) Fluorine (F2) Nitrogen (N2) Chlorine (Cl2)

Compounds Compounds are formed when 2 or more different atoms join. Compounds can be broken down into elements by chemical reactions called decomposition. Common compounds to know: NaCl sodium chloride (salt) H2O water NH3 ammonia CH4 methane CO2 carbon dioxide

Mixtures A mixture is a PHYSICAL blend of two or more substances. Since they are only physically mixed, mixtures can be separated based on certain properties. More on separating mixtures later…

Examples of Common Mixtures System Example Gas-Gas Air Liquid-Gas Water vapor in air Gas-Liquid Soda, shaving cream Liquid-Liquid Vinegar Solid-Liquid Salt water Solid-Solid Sterling Silver

Classifying Mixtures Mixtures can be classified as HOMOGENEOUS HETEROGENEOUS OR

Homogeneous Mixtures a mixture in which the components of the mixture are uniform throughout. Salt water and iced tea are good examples of homogeneous mixtures. Also, the colors green, purple, etc. are mixtures.

Heterogeneous Mixtures Heterogeneous mixtures do not have uniform composition. A good example of a heterogeneous mixture is a salad.

Heterogeneous or Homogeneous?

Practice Substance, element, atom

Practice Mixture, compounds, molecules

Practice Substance, elements, molecules

Practice Mixture, elements, atoms

Practice Mixture, elements, atoms and molecules

Practice Substance, compound, molecules

Aim: How do we separate mixtures? You are given the following mixture how would you separate out each of the components? Which properties would you focus on?

Properties of Matter Physical properties can be observed or measured with out changing the chemical composition (hardness, phase, color, volatility etc.) Chemical properties are related to a substances ability to undergo chemical reactions.

Physical vs Chemical Properties Physcial Properties (characteristics) Chemical Properties (characteristics) Mass Corrosive Volume Flammable Temperature Combustable Density Oxidizer Boiling Point Reducer Melting Point Reacts Hardness Forms new products with … Color Stable Phase (solid, Liquid Gas) Unstable Solubility Anything that describes how it reacts

Reference Table - S Properties of Elements Melting Point, Boiling Point and Density are all physical properties. Examples: What is the boiling point of helium in °C? What volume would a 0.5 g sample of Oxygen occupy at STP? In what phase would Calcium be found at 1000 K?

Separating Mixtures Separating mixtures can be done based on such properties as 1) boiling point, 2) magnetism, 3) solubility,etc.

Distillation Distillation separates mixtures of liquids by boiling point.

Chromatography Chromatography is based on different rates of migration of the components.

Filtration