quantitive chemistry

Cards (34)

  • A mole in chemistry is a unit of measurement that represents the amount of a substance. It is equal to 6.022 x 10^23 particles.
  • the law of conservation of mass is where the total mass of reactants is equal to the total mass of products
  • a metal salt + hydrogen is created when a metal reacts with an acid
  • during hydration steam is reacted with ethane to give ethanol
  • 2 ways ethanol is produced:
    • fermentation
    • hydration
  • to calculate atom economy:
    sum of formula mass of desired product
    --------------------------------------
    relative formula mass of all reactants
    x100
  • Concentration is typically expressed as the amount of solute dissolved in a given amount of solvent or solution.
  • The formula for calculating the concentration of a solution is: concentration = mol / vol.
  • a titration is a method to find how much acid is needed to neutralise an alkali
  • relative formula mass is the sum of all atomic masses in a substance
  • electrodes are made out of carbon
  • in a redox reaction, both oxidation and reduction take place
  • in electrolysis:
    the positive ions=cations
    the negative ions=anions
  • in electrolysis:
    the positive electrodes=anodes
    the negative electrodes=cathodes
  • electrolysis is the use of an electrical current to break down compounds containing ions into their elements
  • a change of 1 unit of pH indicates the concentration of H+ ions has decreased by 10
  • a strong acid is where the H+ ions are fully ionised in water
  • litmus paper changes:
    red=acid
    blue=alkali
  • pH is measured by:
    • universal indicator
    • pH probe
  • the pH scale is a measure of the acidity or alkalinity of a substance
  • a displacement reaction is when a more reactive metal will displace a less reactive metal from its salt
  • reactivity is how easily a substance loses electrons
  • reduction is the:
    • loss of oxygen
    • gain of electrons
  • oxidation is the:
    • gain of oxygen
    • loss of electrons
  • hydration is better than fermentation as hydration has an atom economy of 100%
  • scientists choose pathways with high atom economies as:
    • more money/profit is made
    • less wasted materials
    • sustainable development
  • atom economy is the measure of the amount of reactants that end up as useful product
  • percentage yield is calculated by:
    actual yield
    ----------- x100
    theoretical yield
  • 2 indicators used in titrations:
    • methyl orange
    • phenolphthalein
  • the neutralisation equation is
    H+ + OH- = H20
  • a limiting reactant is when 1 reactant is used up so it stops the reaction going any further
  • the calculation for moles:
    mass(g)
    ------------
    atomic/formula mass (Mr)(g/mol)
  • reactions have a change in mass when:
    • they're carried out in a non closed system
    • they involve a gas that can escape or enter the system
  • mass is conserved in a reaction as no atoms are lost or made