3. Quantitative Chem

    Cards (27)

    • What is the purpose of quantitative analysis in chemistry?
      To determine formulae and reaction equations
    • How do analysts use quantitative methods in chemistry?
      To determine purity and monitor yield
    • Why is classifying chemical reactions important?
      It helps predict chemical behavior and patterns
    • What do chemical equations represent?
      Chemical reactions and communicate ideas
    • What does the law of conservation of mass state?
      No atoms are lost or made in reactions
    • What does a balanced chemical equation ensure?
      Equal numbers of atoms on both sides
    • What is the relative formula mass (Mr) of a compound?
      Sum of relative atomic masses in the formula
    • How does the sum of relative formula masses relate in a balanced equation?
      Reactants' sum equals products' sum
    • How can you calculate the percentage by mass in a compound?
      Using relative formula mass and atomic masses
    • Why might a reaction appear to change mass?
      Gas reactants or products not accounted for
    • What happens when a metal reacts with oxygen?
      The mass of the oxide is greater than metal
    • What should students explain regarding mass changes in reactions?
      Changes in terms of the particle model
    • What is always present in measurements?
      Some uncertainty about the result
    • How can students represent uncertainty in measurements?
      Using the range of measurements about the mean
    • What unit is used to measure chemical amounts?
      Moles, symbol mol
    • How is the mass of one mole of a substance related to its relative formula mass?
      They are numerically equal in grams
    • What does one mole of a substance contain?
      The same number of particles as any mole
    • What is the value of the Avogadro constant?
      6.02×10236.02 \times 10^{23} per mole
    • How does the measurement of amounts in moles apply?
      It applies to atoms, molecules, ions, etc.
    • RAM (relative atomic mass)
      (mass x abundance)+(mass x abundance)/total abundance
    • RFM (relative formula mass/Mr)
      -add all of the mass numbers together (use periodic table)
      -include the small numbers
      -don't include the large numbers (unless it's atom economy)
    • No. moles
      mass of sample(g)/molar mass
      n = m/Mr
    • % atom economy
      (total RFM desired product/total RFM products) x100
      -use big numbers as well when calculating RFM (Mr)
    • Percentage Yield
      (actual/theoretical) x100
      -have to work out mass of something to find theoretical yield (m=nxMr)
    • Concentration
      c = n/v
      (mol/dm^3)
    • Volume
      v = n/c
      (cm^3)
    • mol/dm^3 to g/dm^3?

      -find the Mr of what question asks about (e.g. sodium carbonate)
      -multiply this by the concentration/volume answer you got in mol/dm^3
    See similar decks