Test Review PowerPoint for 7th Period Chemical Equations Reactants and Products Reactants are combined together to create products What are the reactants and products in the following equations? C + 2O Reactants CO2 Product 2H + O Products H2O Reactant What do you notice about these equations? Coefficients-big numbers (in front) Subscripts-small numbers (behind) Chemical Equations • Label the reactants and products on the chemical equation below: • CaCO3 Reactants CaO + CO2 Products Label the reactants and products. On the practice worksheet. • Mg + O2 • 2H2O2 • 2Cu2O + C • FeS + 2HCl • P4O10 + 6H2O • Fe2O3 + C • SO2 + O2 MgO 2 H2O + O2 4Cu + CO2 FeCl2 + H2S 4H3PO4 Fe + CO2 SO3 Law of Conservation of Mass Conservation of Mass • You must end up with the same amount you started with. • Mass cannot be created or destroyed Conservation of Mass • Matter is not created or destroyed Balancing Chemical Equations Balancing Equations Goal- Have the same number of atoms on both sides of the equation. Rules ◦ Coefficients (numbers in front) multiply ◦ You can not change subscripts (numbers behind) ◦ If there is no subscript after an atom, then you know there is only 1 atom present Balancing Equations 1. Write equation 2. Count Atoms H O H O 2 2 2 1 Balancing Equations H 2 O 2 2 H 2 O 4 1 2 3. Use coefficients to balance the equation H O H O 42 2 4 2 Balancing Equations Practice • 2 H2 + O2 2 H2O • H2 + Cl2 2 HCl • 2 SO2 + O2 2 SO3 • 2 Mg + O2 2 MgO Atoms • Modern Atom Model • Nucleus-Protons and Neutrons • Electrons around nucleus, never know the true location Protons • Positively charged particle • In nucleus • Mass 1 amu Neutrons • Neutral (no) charge particle • In nucleus • Mass 1 amu Electrons • Negatively charged particle • In electron cloud (orbitals) around the nucleus • Mass 0 amu Elements • Made of atoms of one kind • The type of element depends on the atomic number, or the number of protons it has • Most elements occur naturally, but some have to be created in a lab Periodic Table • Elements are organized on the Periodic Table according to atomic number and properties of the element Open textbook to pages L14 – L15 Symbol • The abbreviation letters used for each element Atomic Number • Number of protons (each element has a different # of protons) • Number of electrons (same as # of protons so the element is electrically neutral) Atomic Mass • Mass of the Atom or # of the protons plus neutrons • Each proton equals 1 amu and each neutron equals 1 amu (atomic mass unit) How do you find the average number of neutrons in an atom? atomic mass ( rounded) – atomic number Groups • Groups: or Family = columns • Share similar properties • Numbers on top indicate what group it is • Noble gases-Group 18 (or 8A) • Halogens-Group 17 (or 7A) • Alkali metals-Group 1 Periods • Periods = rows • Atomic mass increases from left to right • Number of protons increases from left to right • Number of electrons in the outer shell of the atom increases from left to right • Only hydrogen and helium are in the 1st period Look at L14 –15 or L186 – L187 Reaction Rates Chemical Changes A change in matter that results in one or more new substances. You change what it is. Chemical in the original substance combines with another chemical to create a new substance Evidence of Chemical Reactions or Change https://www.youtube.com/watch?v=cZMkqagL8Ps (2:52) Evidence of a Chemical Reactions Evidence of Chemical Change color •New ________appears •_____ Heat is produced fizzing •Bubbbles or ________ Light is produced •______ solid •Precipitate forms (____ material) Sound is given off •______ reverse •Difficult or impossible to __________ How do we make the reaction go faster? • There are four things that we can change to make the reaction go faster. • They are • Temperature • Surface area • Concentration • Using a catalyst 1. Temperature • When we increase the temperature we give the particles energy • This makes them move faster • This means they collide with other particles more often • So the reaction goes faster. 2. Surface area • If we make the pieces of the reactants smaller we increase the number of particles on the surface which can react. • This makes the reaction faster. The particles on the surface can react When cut into smaller pieces the particles on the inside can react 3. Concentration • If we make one reactant more concentrated, there are more particles in the same volume to react • So the reaction goes faster. There are less red particles in the same volume so there is less chance of a collision There are more red particles in the same volume so there is more chance of a collision so the reaction goes faster http://www.youtube.com/watch?feature=player_embedded&v=kjKyEdrVXJA 4. Using a catalyst • A catalyst is a chemical which is added to a reaction. • It makes the reaction go faster. • The catalyst does not get used up in the reaction. • It gives the reaction the energy to get started Enzyme catalyst http://www.youtube.com/watch?v=XX9Xo6zm_kM&feature=player_detailpage STATES OF MATTER http://www.teachertube.com/viewVideo.php? video_id=274943 Gas matter that has no definite volume or shape. Molecules of a gas are so loosely arranged and move so rapidly that they will fill their container. Liquid matter that has definite volume but not shape. Since the molecules of a liquid are loosely packed and move with greater speed, a liquid can flow and spread. Solid matter that has definite volume and shape. The molecules are packed together tightly and move slowly. http://www.harcourtschool.com/activity/states_of_matter/index.html Simulation activity • Phase change is a physical property of matter • Changing the amount of heat energy usually causes a temperature change. • During a phase change energy is directed to making the phase change so the • temperature does not change http://www.harcourtschool.com/activity/hotpl • Do the following simulations with this link ate/index.html Melting _____________ Freezing _____________ the change from solid to liquid. the change from liquid to solid. Vaporization ______________ the change from liquid to gas. Evaporation ______________ vaporization from the surface of a liquid. Boiling ______________ vaporization from within as well as from the surface of a liquid. Condensation ________________ the change from gas to liquid. Sublimation _________________ the change from solid to gas. Deposition _________________ the change from gas to solid. 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