Stoichiometry

• Chemical equation


  Reactants and products, appropriate arrow (especially in equilibrium unit), states, coefficients
• Types of reactions


  • Synthesis: building
  • Decomposition: breaking apart
  • Displacement (single or double) "steal your girl" like displaces like
  • Combustion (complete or incomplete)
  • Redox
  • Neutralization (a type of decomposition)
• Percent Composition


  How much of the mass of a compound or molecule is made up of its element parts
• Calculating percent composition


  Mass of element/mass of compound x 100, or using molar mass by multiplying how many of each element by its molar mass and then following the same formula
• Empirical Formula


  The lowest possible ratio of each element
• Molecular Formula


  The true number of each atom
• Ionic compounds have the same empirical and molecular formula
• Finding the empirical formula from composition

  Assume a 100 gram sample 2. Write the percent as mass 3. Convert mass to moles 4. Divide by the lowest number of moles 5. Make the ratio whole numbers
• Finding molecular formula from empirical


  Divide mass of molecular formula by empirical formula to find the multiplier
• Combustion Analysis


  A method for determining the empirical formula of a hydrocarbon
• Hydrates


  Ionic compounds with water molecules tucked in between them
• Anhydrate


  The ionic compound by itself, without the water molecules
• Naming hydrates


  Compound name + prefix hydrate
• Calculating percent water in a hydrate

  Divide mass of water by the total mass, can be done with mass or chemical formula. For the second, uses the relative atomic masses to find total mass and the mass of just the water component
• Calculating the formula of a hydrate

  Mass to moles, divide by the smallest mole number, and find the ratio. The anhydrate should always have the smaller mole number
• Particulate nature of matter

  • Matter has mass, makes up everything, particles are always in motion, matter is made of particles
• Energy input or output


  Changes the movement of the particles, normally measured in heat
• Endothermic


  Heat is absorbed
• Exothermic


  Heat is released
• Kinetic energy


  Movement of particles measured as an average
• Potential energy


  Stored or invisible energy that gives it power to create kinetic energy
• Heating/cooling curves


  • Increase in kinetic energy as temperature increased, plateau with potential energy during state changes
• Mole


  A huge quantity of 6.02 x 10^23 particles, known as Avogadro's number
• One mole of any element equals its molar mass
• Molar highway


  Used to switch between moles, mass, particles and volume
• Gas measured at STP

  22.7/L at 25°C and 101.9 kPa
• Percent Yield


  Actual yield/theoretical yield x 100
• Solute


  The dissolved substance
• Solvent


  The dissolving medium
• Solution types


  • Unsaturated: does not contain the max amount of solute
  • Saturated: contains the max amount
  • Saturated to excess: more solute is added and will the undissolved
  • Super saturated: saturated to excess but heated to dissolve
• Concentration


  Moles/volume
• Soluble compounds contain


  • H, NH4, Li, Na, K, NO3
• Net ionic equation


  Removes spectator ions
• Ideal gas conditions


  • Particles are not attracted to each other, have negligible volume, high temperature means low pressure
• Kinetic Molecular Theory


  • Particles move in rapid random and straight motion, run into each other and the confines of the container, pressure has to do with the amount of collisions which stems from the amount of gas particles, mostly empty space in which particles move
• Avogadro's law


  One mole of any gas = 22.7 dm^3 and 6.02x 10^23 particles at STP
• Boyle's law


  When temperature remains constant, pressure is inversely proportional to volume P1V1=P2V2
• Charles' law


  When pressure remains constant, temperature is proportional to temperature V1/T1= V2/T2
• Gay-Lussac's law


  When volume remains constant, the relationship between pressure and temperature is proportional
• Combined gas law


  P1V1/T1 = P2V2/T2