1_chemical formula and equation

1_chemical formula and equation

1. Chemical Reaction

   • Is a process where one or more substances is changed into one or more new substances
     • Is a process where one or more substances is changed into one or more new substances
     • Reactants to Products
       • Solute
         • Substance that dissolves in solvent
       • Solvent
         • Substance that dissolves solute
           • Solute+solvent+solution
       • Solution
         • Homogeneous mixture of 2 or more substances
   • Avogrado's Constant
     • Number of atoms in 12g of carbon-12 atom
       • 6.002x10^23
   • Moles
     • Number of atoms and molecules
       • Number of moles(mol)=mass(g)/molar mass(g mol^-1)
         • Number of moles(mol)=mass(g)/molar mass(g mol^-1)
   • Molar Volume
     • Standard temperature and volume:22.4L mol^-1
       • Volume occupied by 1 mol of gas
   • Chemical formulaes
     • Molecular formula
       • Chemical formula which shows the actual number of atoms in an element
         • n(empirical formula)
     • Empirical formula
       • Chemical formula which shows the simplest ratio of atoms of an element
         • Steps
           • 1)Determine the mass or percentage(by 100g) of elements in the compound
             • 1)Determine the mass or percentage(by 100 g) of elements in the compound 2)Divide the mass/percentage of elements with respective relative atomic mass 3)Divide by the smallest number to obtain the ratio 4)Write the empirical formula from the ratio of the elements
             • 2)Divide the mass or percentage of elements with the respective relative atomic mass
               • 3)Divide with the smallest number to obtain the ratio
                 • 4)Write the empirical formula from the ratio of the elements

2. Concentration of Solutions

   • A solution is a homogenous mixture of two or more substances
     • solvent + solute(s)
   • Expression
     • Mole Fraction (X)
       • Xa = moles of a / sum of moles of all components
     • Percentage by mass and volume
       • %w/w = (Mass of X / Mass of sample) x100%
       • %w/V = (mass of X (g) / Volume) x100%
       • %v/v = (Volume of X / Volume of Sample) x100%
     • Molality
       • Molality,m = moles of solute (mol) / mass of solvent (kg)
     • Molarity
       • Molarity = moles of solute / liters of solution
       • Units
         • mol L^-1
         • mol dm^-3
         • M