Module 2 chemistry

• Ions are created when electrons are transferred from one atom to another, attracting each other to form compounds
• Formation of compounds


  Ions are created when electrons are transferred from one atom to another, attracting each other to form compounds
• Ionic compounds


  • Zinc iron (2+)
  • Silver (Ag+)
• Working out the formula of an ionic compound


  Swap the charges, drop the charges, combine and simplify
• Salts are an example of an ionic compound, can be hydrated or anhydrous
• Water of crystallization


  Water molecules within crystal structures of salts, indicated by formulas like CuSO4•5H2O
• Calculating water of crystallisation

  Heating the salt to remove water and determine the value of water crystallisation
• Calculating number of moles

  Number of moles = Mass in grams / MR (Atomic or Molecular Mass)
• Calculating number of moles in a solution

  Number of moles = Concentration (moles per dm^3) x Volume (dm^3)
• Ideal Gas Equation


  PV = NRT (Pressure x Volume = Number of moles x Gas Constant x Temperature)
• Units are quite important here
• Three different types of dimension: one-dimensional units, two-dimensional units, three-dimensional units
• Converting units from meters to decimeters and decimeters to centimeters

  Decimeter means a decade, 1/10 of a meter, 10 centimeters in a decimeter, 10 decimeters in a meter, 100 centimeters in a meter
• Converting units from decimeters to centimeters

  Decimeter means a decade, 1/10 of a meter, 10 centimeters in a decimeter, 10 decimeters in a meter, 100 centimeters in a meter
• Converting units from meters to centimeters

  100 centimeters in a meter
• Converting units for volumes

  Adding a zero for each additional dimension, multiplying by 100 for meters squared to decimeters squared, multiplying by 10,000 for meters squared to centimeters squared, multiplying by 1,000 for meters cubed to decimeters cubed, multiplying by a million for meters cubed to centimeters cubed
• State symbols: S for solid, L for liquid, G for gas, AQ for aqueous (dissolved in water)
• Calculating theoretical mass from an equation


  Calculate the relative atomic mass (RAM) or atomic mass (AM) of the species involved, use the masses in grams, determine the theoretical mass based on the balanced equation
• Calculating volume of a gas from an equation

  Use balanced equations to calculate the volume of a gas, consider the gas constant (8.31 J/K/mol)
• Gas constant is 8.31 joules per Kelvin per mole
• Equation balancing


  2 moles of potassium react to produce 1 mole of hydrogen
• Volume of hydrogen gas produced is 3.84 x 10^-3 meters cubed
• Empirical formula calculation


  Divide the moles of each element by the smallest number of moles to determine the empirical formula
• Empirical formula of the compound with 23.3% magnesium, 30.7% sulfur, and 46.0% oxygen is MgSO3
• Molecular formula calculation


  Divide the MR of the empirical formula by the MR of the molecular formula to determine the multiplier for the molecular formula
• Combustion reaction results in 0.485g of carbon dioxide and 0.173g of water
• Empirical formula calculation for a hydrocarbon

  Determine the moles of carbon and hydrogen based on the combustion products