1.2 amount of substances

• calculation for moles

  moles = mass / mr
• 1 tonne = (g)

  × 1000000
• 1kg->

  × 1000
• 1mg-> grams

  / 1000
• percentage yield

  % yield = mass of product / theoretical mass of product $\times$100
• atom economy

  atom economy = mr of desired product / total mr of reactants $\times$100
• ideal gas equation

  PV = nRT
• dm$^3$in m$^3$


  /1000
• cm$^3$to m$^3$


  /1000000
• Kpa to pa

  $\times$1000
• MPa to pa

  $\times$1000000
• $\degree$c to K


  + 273
• whats the ionic formula for nitrate

  NO3$^-$
• whats the ionic formula for carbonate

  CO3$^2-$
• whats the ionic formula for sulphate

  SO4$^2-$
• whats the ionic formula for phosphate

  PO4$^3-$
• whats the ionic formula for ammonium

  NH4$^+$
• ionic formula for hydroxide

  OH$^-$
• define moles?

  the amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12
• define relative atomic mass:

  the average mass of one atom compared to one twelfth of the mass of one carbon-12 atom
• define relative molecular mass:

  the average mass of one molecule compared to one twelfth of the mass of one carbon atom
• what is avagadros number?

  there are 6.022×10^23 atoms in 12 grams of carbon-12
• how do i find moles using cocentration?

  c × v = n
• how do i calculate the number of particles? (using avagadros.)

  number of particles = moles × avagadros constant
• when calculating the emperical formula what numbers do we use to get to the whole number ratio?

  • .5 -> × 2
  • .33 / .66 -> × 3
  • .25/.75 -> × 4
• define emperical formula

  the simplest ratio of atoms of each element in a compound
• define molecular formula?

  the actual number of atoms of each element in a compound
• how do you find the molecular formula using the emperical formula?

  find the mr of the emperical formula , then divide by the molecular formulas mr and the emperical formulas mr , multiply the emperical formula by that number
• how do i find the mr using mass spectrometer?

  the molecular ion which is the ion with the peak with the highest m/z ratio is equal to the mr
• hydrated salt contains...?

  water of crystalisation
• how do i find mass concentration?

  mass/volume = concentration
• how do i convert moldm^-3 to gmol^dm-3 ?

  multiply by Mr
• when calculating atom economy, do use balancing numbers when calculating mr
• why do chemists use atom economy?

  to find how much of the reactants is used in the product and minimising by-product
• why do chemists use percentage yeild?

  do find how efficient conversion is from reactants to products