Chemistry

Chemistry

1. Binary solids (chemical bonds)

   • Ionic bonds-compounds are composed of metals and non-metals. The metals are the cations. The non-metals are the anions.
     • bond that holds the cation and anion together is called an ionic bond.
       • ionic compounds-can dissolve in water, hard and brittle, high melting points
         • conduct electricity
           • ex. NaCl, sodium wants to lose one and chlorine wants to gain one.
             • use cris cross method to figure out charge.
       • metal ions have more than one possible charge in nature.
       • Polyatomic ions, are several ions clumped together to form a group, they share an overall share.
   • Covalent bonds- occur between non metals, atoms share valence electrons. to complete their valence shell.
     • ex. Hydrogen gas found in nature as H2, shares there two valence electrons
       • molecular compounds- particles where two or more elements are joined by covalent bonds
         • diamtomic molecule only has two types of atoms
           • will not occur in nature as single atoms,they will always be part of another molecule or pair with another atom like it, to form gases.
             • 'Have No Fear Of Ice Cold Beer' H2,O2,F2,O2,I2,Cl2,Br2
         • Name molecular compounds: mono, di,tri,tetra,penta,Hexa,Hepta,Oct,Non,Dec
   • Periodic Table: Groups is the columns, how many slots are filled, Periods are the rows
     • placement of the elements in periodic table tells you how it will react with other elements
       • Group 1: (-hydrogen) alkali metals, soft highly reactive)
         • Group 2: alkaline earth metals, light,reactive
           • Group 17: Halogens, these non-metals are highly reactive.
             • Group 18: noble gases, do not react with other elements
     • ions: Atoms that lose electrons form cations, and then have a positive electrical charge. Metals usually become the cation. Atoms react with other atoms to form a full valence shell

2. Chemical reactions

   • Evidence of chemical change
     • New colour, new substance is formed
     • Formation of solid material appears in a liquid
     • Heat and light is produced.
     • Bubbles of gas are produced
     • change is difficult or impossible to reverse
   • types of equatiions: word equation, describes the chemical reaction using their full names, and a chemical equation describes a chemical reation using the chemical formula's
     • reactants: substances used in the reaction
       • Products produced during the reaction
     • indicating states in an equation: solid(s), liquid(l), gas(g), Aqueous- dissolved in water(aq)
     • Chemical reactions
       • synsythesis reaction: reaction in which two reactants combine to make a larger more complex product general pattern: A+B
       • single displacement: reaction where one element replaces another in a compound to form a new element,general patterb: A+BC+B
       • double displacement: reaction where two elements in different compounds trade places
         • Neutralization: acid and a base react to produce an ionic salt and water. This essentially a double displacement.
           • neutralization reactions in real life
       • Decomposition reactions: reactants where a larger or complex molecule breaks down to form 2 or more simpler products.
         • Combustion: Reaction where a substance reacts with oxygen to produce oxides and energy (heat and light) Usually use a hyrocarbon sometimes oxygen as fuel.
           • incomplete combustion: O2 is limited produces soot, water,and energy
             • complete combustion: lots of O2, CO2 AND H2O produced
           • Alkali metals and alkaline earth metals will all react with oxygen.
             • Don't need to burn metals to make oxides. They may occur by reacting to elements in the air, nature.
   • Law of conservation of mass: Total mass of reactants equals the total mass of the products in any given chemical reaction.
     • Skeleton Equations: matter cannot be created or destroyed so,all the atoms in the reactants must also appear in the products
       • Balancing Equations: Add coefficients in front of each compound until the same number of each type of atom appears on both sides of the equation.
         • Subscripts tell you how many atoms of that element are in the molecule.

3. Acids and Bases

   • Acids: release hydrogen ions when dissolved in water. molecular compounds
     • sour taste, feel wet and clean in solution, water soluable
   • Bases: release hydroxide ions (OH-)
     • pH: how basic, acidic or neutral a compound is
       • 7-neutral
       • <7-acidic
       • >7-basic
       • Acid leaching: used to clean heavy metals
       • Photoremeadiation
       • Acid rain: pH less than normal rain, acidic, kills aquatic ecosystems,