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Matter Pure Substances Elements Compounds & Molecules Mixtures Homogeneous Heterogeneous Solution Matter Matter is anything that has MASS and takes up SPACE Law of Conservation of Mass: Matter cannot be created or destroyed Matter Examples of Matter: • Water • Chex Mix • Plastic • Humans • Air Examples that aren’t Matter: • Space • Light • Sound • Energy • Heat Nucleus: Middle of the atom, made up of protons (+ charge) and neutrons (no charge) The Atom: The unbreakable building blocks that make up all matter Electrons ( - charge) Physical Properties All matter has physical and chemical properties Physical Properties are properties that you can measure or see Examples: mass, density, color, temperature, malleability and brittleness, phase (solid, liquid, gas) Physical Changes Physical changes change the physical properties but DO NOT change the matter into something else • Phase Changes • Changing Shape Physical Changes are reversible Chemical Properties Chemical Properties are properties that allow the ability for a chemical change/reaction to occur They can only be observed when matter goes through a chemical change, can’t know just by looking at it Examples: Flammability, Ability to react with specific materials Chemical Changes Chemical Changes: Any Signs of a Chemical Change change that changes one substance into a different substance Created by a chemical reaction Chemical changes are very difficult or impossible to undo Types of Matter Matter is separated into two major categories: 1) Pure substance cannot be separated into different kinds of matter by physical means and are made up of one single chemical throughout 2) Mixtures are made up of multiple substances Most matter in the world around us are mixtures Matter Pure Substances Elements Compounds & Molecules Mixtures Homogeneous Heterogeneous Solution Elements Element: a substance that cannot be separated into simpler substances by chemical means • Each element is a unique type of atom • Atoms of the same element are all similar to each other and different from atoms of any other element • Elements are located on the periodic table Periodic Table Layout Organized into periods (rows) and groups (columns), elements separate from the table are part of Periods 6 and 7 Periodic Table Element Symbol: 1 or 2 letters that represent the element First letter is ALWAYS capitalized, second letter NEVER is Atomic Number: Number of Protons Atomic Mass The atomic mass listed for an element on the periodic table is the mass of a single atom in atomic mass units (amu) 1 amu = 1.66 x 10-24 grams Atomic mass units are not practical for experiments, our balances can’t measure a mass that small Atomic Mass To turn amu into something more usable in lab we use a unit called the mole 1 mole = 6.02 x 1023 atoms This is Avogadro’s Number Atomic Mass = Number of grams in 1 mol Calculating Moles using Atomic Mass Use atomic mass as a conversion factor between moles and grams How many moles are in a 10.0g sample of Carbon? 10.0 grams x 1 mole = 0.833 moles 12.01g Try it on your own You have 20 grams of Helium, how many moles do you have? Calculating Mass from Moles You have 5 moles of Nitrogen, how many grams do you have? 5 moles x 14.00 grams = 70 grams 1 mole Try it on your own You have 2 moles of Lithium, how many grams do you have? Matter Pure Substances Elements Compounds & Molecules Mixtures Homogeneous Heterogeneous Solution Review - Types of Matter Matter is separated into two major categories: 1) Pure substance cannot be separated into different kinds of matter by physical means and are made up of one single chemical throughout 2) Mixtures are made up of multiple substances Most matter in the world around us are mixtures Compounds and Molecules Compounds and molecules are pure substances They cannot be separated by physical means but can be separated by chemical means Their physical and chemical properties come from the shape of the molecule, not from what they are made of Compounds vs. Molecules A molecule is ANY group of atoms chemically bonded together Examples: H2 (Hydrogen Gas) CH4 (Methane) N2 (Nitrogen Gas) Compounds vs. Molecules A compound is a substance containing DIFFERENT elements that are chemically bonded together. Examples: H2O (Water) C2H6O (Ethanol) NaCl (Salt) Almost everything in this world is made of compounds! Understanding Chemical Formulas Chemical formulas are written using element symbols Remember: Element symbols can have either 1 or 2 letters and ALWAYS start with a capital letter! Chemical Formula Practice How many different elements are in each molecule? NaCl KI HCN KCl MgO Xe Subscripts Subscripts are used to tell you how many copies of an element is in a molecule H2 = 2 Hydrogen in one element H2O = 2 Hydrogen, 1 Oxygen in one element Practicing Reading Subscripts H(CO3)2 H2SO4 How many H’s How many H’s? How many C’s How many S’s? How many O’s How many O’s? Molar Mass Molar mass = Number of grams in one mole of the molecule You need to add up the atomic mass of each element (multiplied by any subscripts) to get the total mass of the molecule Practicing Molar Mass Molar Mass of HCN Mass of Hydrogen: 1.008 Mass of Carbon: 12.01 Mass of Nitrogen: 14.01 Molar Mass of H2SO4 Mass of H: 1.008 x 2 Mass of S: 32.07 Mass of O: 16.00 x 4 Molar Mass of HCN = 1.008 + 12.01 + 14.01 = 27.03 g/mol Molar Mass of H2SO4 = 2.016 + 32.07 + 64.00 = 98.09 g/mol Converting between grams and moles for molecules Converting between grams, moles, and atoms is the same process for molecules as it is for individual elements Instead of using atomic mass to convert between grams and moles you need to use the molar mass of the molecule Molecule Conversion Example You have 100 grams of Table Salt (NaCl), how many moles do you have? 100g NaCl x 1 mol NaCl = 1.71mol NaCl 58.44g NaCl Molar Mass Molar mass = Number of grams in one mole of the molecule You need to add up the atomic mass of each element (multiplied by any subscripts) to get the total mass of the molecule Percent (%) Composition Remember from Lab 1C % composition = mass of the part x 100 mass of the whole We can find the Percent Composition of a molecule the same way Percent Composition of Molecules % comp = molar mass of element x 100 molar mass of molecule Example: What percentage of the mass of H2SO4 comes from the Oxygen? Mass of O: 16.00 x 4 = 64 g/mol Mass of H2SO4: 98.09 g/mol % Oxygen: (64/98.09) x 100 = 65.2% Percent Composition Example Find the Percent Composition of both Copper and Chlorine in CuCl2 Molar Mass of Copper: Molar Mass of Chlorine: Molar Mass of Molecule: % composition of Copper: % composition of Chlorine: Matter Pure Substances Elements Compounds & Molecules Mixtures Homogeneous Heterogeneous Solution Mixtures Mixtures: Matter that contains more than one substance Mixtures can be separated by physical means - sorting, filtering, heating, or cooling Types of Mixtures Homogeneous Mixtures looks the same throughout Heterogeneous Mixtures look different throughout Examples of Mixtures Decide whether each mixture is a homogeneous mixture (HoM) or a heterogeneous mixture (HeM) Soap Chocolate Chip Cookie Granite Gatorade Shampoo Chex Mix Sand Lemonade Granola Bar Milk Matter Pure Substances Elements Compounds & Molecules Mixtures Homogeneous Heterogeneous Solution Solutions Solutions are a specific type of homogeneous mixture where one substance (solute) gets dissolved in another substance (solvent) The substance being dissolved (the solute) completely breaks down and gets absorbed by the solvent: Examples: Salt Water, Pop, lemonade