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Chemistry Ch 7A
Chemistry 101
| Question | Answer |
|---|---|
| Chemical Reactions | a process in which atoms of different elements can combine/ decompose to make new compounds,atoms can be exchanged or transferred and gain or lose electrons |
| Elements are not...? | transmuted during a reaction |
| Evidence of Chemical Change | heat,light, color change,gas, and formation of precipitate |
| Chemical Equations are | a shorthand way of describing a reaction |
| Energy Symbols | D=Heat, Hn=light, shock= mechanical, elec- electrical |
| In balanced chemical equations | The # of atoms of each element in reactants = the # of atoms in products |
| In writing balanced equations | you 1. Write a skeletal equation by writing the formula of each reactant and product 2. Count the number of atoms of each side of the equation(Poly ions sometimes = 1 element) 3.Pick an element to balance |
| How do you pick which elements to balance first | if an element is found in only one compounds on each side, balance it first, balance metals before non-metals, if an element is free on either side of the equation balance it last |
| Synthesis/Combination | A + B = AB ( Two or more reactants combine to form one product) |
| Decomposition | AB = A +B ( One substance splits into two or more simpler substances) |
| Single Displacement | A + BC = AC +B ( One element takes place of another element) |
| Double Displacement | AB + CD = AD +CB ( Two elements in the reactants exchange places) |
| Aqueous Solutions | dissolving chemicals in water reacts faster, water separates the chemicals into individual molecules or ions, free-floating particles come in contact more frequently so the reaction speeds up |
| Dissociation | when ionic compounds dissolve in water the anions and cations are separated from each other |
| Dissociation of Polyatomic Ions | the groups stay together as one functioning ion |
| Strong electrolytes | all the electrolyte molecules or formula units are separated into ions. |
| In weak electrolytes | a small percentage of the molecules are separated into ions. |
| In nonelectrolytes | none of the molecules are separated into ions. |
| Types of Electrolytes | Salts = Water soluble ionic compounds. Acids = Form H+1 ions and anions in water solution. Strong acid = strong electrolyte, weak acid = weak electrolyte. Bases = Water-soluble metal hydroxides. Increases the OH-1 concentration. |
| precipitation reactions | If a chemical reactions between ions in aqueous medium result in insoluble salts, and the insoluble salt will come out of solution as a precipitate. |
| Are all ionic compounds, salts , water soluble | no |
| CO32-, S2-, PO43-, OH- are soluble with | NH4+, Li+, Na+, K+ |
| Cl-, Br-, R are not soluble with | Ag+, Pb12+, Hg22+ |
| SO42- | Ba2+, Pb2+, Ca2+, Sr12+ |
| Molecular equations are | Equations that describe the chemicals put into water and the products formed. |
| complete ionic equations are | Equations that describe the actual dissolved species in water |
| net ionic equation is | An equation in which the spectator ions are removed |
| Properties of Acids are | sour taste, react with active metals, are corrosive, react with carbonates, and react with bases to form ionic salts |
| Properties of Bases are | A.k.a. alkali's. Taste bitter. Feel slippery. Change color of litmus and vegetable dyes. Different color than acid. Litmus = blue. React with acids to form ionic salts. And often water. Neutralization. |
| neutralization reactions are | acid-base reactions, The H+1 from the acid combines with the OH-1 from the base to make water, and The cation from the base combines with the anion from the acid to make the salt. |
| Gas Evolution Reactions | Reactions in which one of the products escapes as a gas are called gas evolution reactions, Some reactions directly form a gas from the exchange of ions, In other reactions, the decomposition of one of products result in a gas and water. |
| Oxidation–reduction reactions are | The element that loses electrons in the reaction is oxidized. The substance that gains electrons in the reaction is reduced. Oxidation and Reduction are simultaneous. |
| Combustion Reactions | Combustion reactions: Reactions in which O2 is consumed by another substance. Always release heat and/or other forms of energy. Produce one or more oxygen-containing compounds. |
| Gain of Oxygen Loss of Oxygen | Oxidation Reduction |
| Gain of Hydrogen Loss of Hydrogen | Reduction Oxidation |
Created by:
mada22