Chemistry Unit 1

Chemistry Unit 1

Formulae, Equations and Amount of Substance ALWAYS LOOK AT THE SYMBOL GIVEN (g OR dm³, etc.)
1. Empirical Formula: %/ram = x for each element, x/smallest value, then ajust
2. Ionic Equations: Write out full molecular formula, balance, separate into ions, look if soluble or not, then cancel spectator ions and re-write
3. Moles = mass/molar mass OR n=m/Mr
  1. For Gases: moles= volume(dm³)/Molar volume(24) OR n= v/Mv (24dm³molˉ¹)
  2. 4 Solutions: moles=concentration(moldmˉ³)Xvolume(dm³) OR n=cv REARRAGE: c(moldm³)=n/v WATCH OUT 4 CONVERTIONS cm³->dm³ 1cm³->0.001dm³ 1dm³->1000g
4. Calculations based on reactions
  1. To get Mass B from Mass A: mass A -> moles A -> moles B -> mass B
    1. Moles A -> Moles B: moles A x ratio B/A
5. Calculation of No. of Particles: No. molecules = Moles x Avogadro =>no. MOLECULES=nx6.02x10²³ =>no. IONS=no.molecules x No. of ions in the formula
6. Concentration of Solutions:
  1. amount of solute(moles)/volume(dm³) = moldmˉ³
  2. amount of solute (grams)/volume(dm³) = gdmˉ³
  3. [amount of solute (grams) / amount of solution {solute + solvent} (grams)x10^6] x 10^6/10^6=ppm TRY N WORK IT OUT SYSTEMATICALLY! USE X IF NEED BE!
    Anotações:
    - video with explaining ppm in greater depth: http://www.youtube.com/watch?v=d6MxhXPmyes
7. Gas Volume Calculations
  1. To get Volume B from Mass A: mass A -> moles A -> moles of gas B -> volume of GAS B
    1. Moles A -> Moles B: moles A x ratio B/A
      1. Moles of gas B -> Volume of GAS B: moles B x molar volume
  2. Calculations for GASES ONLY: ratio B/A x mass A = volume of GAS B
    Anotações:
    - For Calculations involving gases only, you can skip using the molar mass or volume because you divide and then multiply the same number. So: ratio B/A x Mass A = volume of gas Bis all the working that is needed!
8. Percentage yield (%) = (actual yield/theoretical yield) x 100
9. Atom economy = (Mr of product [that you want!!] x No. of formulae of it in the equation x 100) / sum of Mr of all reactants
Introduction to Organic Chemistry
Atomic Structure and The Periodic Table
Energetics
1. Exothermic reaction = bond breaking ∴ loses heat energy to surroundings ∴ change in enthalpy is negative (-ΔH)
2. Endothermic reaction = bond making ∴ gains heat energy from surroundings ∴ change in enthalpy is positive (+ΔH)
3. The activation energy is the energy required by certain chemicals to undergo a reaction
4. E=mcΔT
  Anotações:
  - E=mcΔT E- Energy transfered m- mass c- specific heat capacity ΔT- change in temperature (Specific Heat Capacity- The energy in joules (j) needed to raise the temperature of 1Kg of a substance by 1 Kelvin)
5. ENTHALPY OF REACTION: is when the molar quantities as written in the equation react under standard conditions (1atm pressure + a stated temp of 298K)
6. ENTHALPY OF FORMATION: is the enthalpy change when 1 mole of a compound is formed from its elements under standard conditions
7. ENTHALPY OF COMBUSTION: is the enthalpy change when 1 mol of a substance if burnt completely in oxygen under standard conditions
8. ENTHALPY OF NEUTRALISATION: is the enthalpy change when an acid and base react to form 1 mol of water under standard conditions
9. HESS'S LAW: Law which states that the energy change in an overall chemical reaction is equal to the sum of the energy changes in the individual reacti
Bonding
Weak Points

Próximo

Descrição

Resumo de Recurso

Semelhante

	Criado por Omar Amura mais de 11 anos atrás