WARM UP WEDNESDAY, NOV. 11 Explain how a chemical formula indicates the ratio of elements in a compound. WEDNESDAY, NOVEMBER 11, 2015 Warm up Notes on chemical formulas and equations Chemical formula worksheet Homework Vocabulary flash cards quiz on Friday CHEMICAL FORMULAS AND EQUATIONS PHYSICAL AND CHEMICAL CHANGES Physical Change A change only affecting physical properties Chemical Change A change to produce a new substance or change the properties of the original substance The process that produces a chemical change is a chemical reaction CHEMICAL REACTION To describe a chemical reaction you have to know 1. which substances react 2. which substances are formed in the reaction. Reactants: The substances that exist before the reaction begins Products: The substances formed as a result of the reaction The arrow between the reactants and products represents the changes that occur during the chemical reaction. CHEMICAL EQUATION Chemical formulas describe what is happening in a chemical equation. A chemical Equations help us to quickly identify what elements are involved (reactants) and what substances are produced (products). They also tells us the proportions of each substance present. PRACTICE LABEL THE REACTANTS IN THE FOLLOWING CHEMICAL EQUATIONS: PRACTICE LABEL THE PRODUCTS IN THE FOLLOWING CHEMICAL EQUATIONS: USING WORDS TO NAME CHEMICAL EQUATIONS Chemical equations can be represented with words or formulas: Na + Cl NaCl Sodium + Chlorine (Produces) Sodium Chloride H + H2O H3O Hydrogen + Water (Produces) Hydronium Ion COMMON CHEMICAL FORMULAS Familiar Compounds Familiar NameChemical NameFormula SandSilicon DioxideSiO 2 Milk of MagnesiaMagnesium HydroxideMg(OH) 2 Cane SugarSucroseC 12 H 22 O 11 VinegarAcetic AcidCH 3 COOH What are the elements in Sucrose and how many of them are them? LAW OF CONSERVATION OF MASS Mass cannot be created or destroyed it can only change form. The mass of the reactants always equals the mass of the products BECAUSE OF THE LAW OF CONSERVATION OF MASS The number of atoms on the left side of the arrow has to equal the number of atoms on the right side of the arrow. EQUATIONS Subscript: Small number below a chemical symbol. Tells how many atoms of that element there are in a compound Coefficient: Large number in front of a compound. Tells how many molecules of that compound there are (distributive property) ENERGY IN CHEMICAL REACTIONS When bonds break and form during chemical reactions, energy can be released or absorbed in the form of light, heat, or sound. If heat energy is absorbed in a chemical reaction it is called an endothermic reaction If heat energy is released in a chemical reaction it is called an exothermic reaction WARM UP NOVEMBER 12, 2015 Vocabulary review THURSDAY, NOVEMBER 12, 2015 Warm up Finish Understanding Chemical Formulas Understanding chemical equations Hand out unit study guide due on Tuesday Vocab quiz Friday and flash cards WARM UP NOVEMBER 13, 2015 How many atoms of each elements are in the following formulas? CO 2, NaCl, H 2 0, NH 3 Draw electron dot diagram for the following atoms H, Ca, K, Ne FRIDAY, NOVEMBER 13, 2015 Warm up Turn in flash cards Vocabulary quiz Work on matter review Unit study guide due on Tuesday. WARM UP NOVEMBER 16, 2015 How many atoms of each element is in the following equation and is the equation balanced? C 3 H O 2 3 CO H 2 0 MONDAY, NOVEMBER 16, 2015 Warm up Matter review worksheet WARM UP NOVEMBER 17, 2015 What is the difference between endothermic and exothermic reactions? TUESDAY, NOVEMBER 17, 2015 Warm up Check study guide for completion Review study guide