1.02 amount of substance

• what is T in the ideal gas equation and what are its units?

  temperature (K).
• what is the conversion from cm^3 to dm^3?

  divide by 1000.
• what is avagadros constant?

  6.022 x 10^23.
• how do you calculate Mr?

  mass/moles.
• how do you calculate concentration?

  moles/volume.
• what is the conversion between cm^3 dm^3 and m^3?

  1,000,000cm^3 = 1,000dm^3 = 1m^3.
• what is P in the ideal gas equation and what is its units?

  pressure (Pa)
• how do you calculate moles in a gas?

  volume/24.
• what are the two calculations to find moles?

  mass/mr conc X volume
• what is standard (room) pressure?

  1 ATM (100,000 Pa)
• what is the conversion between ATM, KPa, and Pa?

  1ATM = 100KPa = 100,000Pa
• what does STP stand for?

  standard temperature and pressure.
• what does N stand for in the ideal gas equation and what are its units?

  number of moles (mols).
• how do you convert degrees C to K?

  degrees C + 273 = K
• how do you convert conc (g dm^3) to conc (mol dm^3)?

  conc (g dm^3) / Mr = conc (mol dm^3)
• what is V in the ideal gas equation and what are its units?

  volume (m^3)
• what is standard (room) temp?

  25 degrees (298K)
• how do you calculate mass? give two formulas.

  density x volumeMr X moles
• how do you calculate the volume of a gas?

  moles X 24
• what is the value of R in the ideal gas equation?

  8.31
• what is the conversion between mg, g, and kg?

  1,000,000mg = 1,000g = 1kg.
• what is an empirical formula?

  the simplest whole number ratio of each element in a compound.
• how do you calculate volume?

  moles / conc
• what is the ideal gas equation?

  PV=nRT
• what is the conversion between Pa, KPa, and MPa?

  1,000,000Pa = 1,000KPa = 1MPa.
• how do you calculate empirical formula?

  calculate moles (mass/Mr) divide all moles by the smallestwrite the formula fully
• what does the molecular formula show?

  the actual number of atoms in each element of a compound.
• how do you calculate percentage yield?

  actual yield/theoretical yield x 100
• give three reasons why % yield is not 100%.

  reactant left in apparatus side reactions reversible reactions
• how do you calculate atom economy?

  Mr of desired product / Mr of all reactants x 100
• give three reasons why a high atom economy is important.

  less waste/more environmentally friendlycheapermore sustainable/ efficient use of raw materials
• how do you calculate the mass of limiting reactants?

  find moles of reactants ice table calculate mass (moles x Mr)
• how do you calculate ionic equations?

  write out the full equationwrite the equation as ionscancel out the spectator ions that appear on both sides
• as the pH of a solution increases by 1 what happens to the concentration of H+ ions?

  it decreases by a factor of 10
• what are the steps to calculation titrations?

  calculate moles of A (conc X vol) ratio A:B calculate conc of B
• what are the steps to calculating 2 step titrations?

  draw a diagram calculate moles in the burette (conc X vol) ratio moles to find moles in conical flask calculate moles in the STD solution
• what are the steps to calculating back titrations?

  calculate moles in the burette calculate moles in 250cm^3 flask by scaling the ratio calculate how mm any moles reacted (original - left over) calculate the moles of solid using the ratio in the formula
• Why can we use distilled water to flush out flasks in titrations?

  water does not change the number of moles of each reactant
• why is a conical flask preferred over a regular beaker in titrations?


  easier to swirl without spills
• why is high atom economy good?

  desirable for industrial processes as is it better for the environment as it produces less waste. it is also a more efficient use of raw materials and waste is minimised so it is sustainable. additionally there is less waste and impurities so it is cheaper