Chapter 2 - Amount of Substance

the average mass of an atom relative to one twelfth of the average mass of a carbon 12 atom average mass of one atom of an element*12/mass of one carbon-12 atom

the same as relative atomic mass but the average mass of one molecule you can find this mass by adding up all the relative masses in a molecule

a way to measure the mass of one repeating unit in an ionic compound because they dont exist as molecules but rather a giant lattice

6.022 x 10^23

the number of atoms or molecules in one mole of a substance one mole of a substance is equal to the Mr or Ar in grams The Avogadro constant or Avogadro number is the number of atoms in 12 g of carbon-12.

(mass/1000)/6.022*10^23

the substance that is dissolved in a solvent

the substance that dissolves the solute

a combination of a dissolved solute and a solvent

the amount of a substance in one dm^3 of said substance

as long as the temperature is constant, the product of the pressure and the volume is constant

The volume is proportional to the temperature as long as the pressure remains constant pressure/temperature = constant

The pressure is proportional to the temperature as long as the volume remains constant. pressure/temperature = constant

pV=nRT

a substance of an unknown concentration is titrated with a substance of a known concentration in excess. the resulting mixture is titrated with another substance of known conc. the moles reacted can be subtracted from the total moles used to find how many moles reacted in the initial reaction. this can then be used to find the concentration of the unknown substance.

when the reaction is slow, the substance is not pure, the reaction is difficult to observe, the analyte is a non-soluble solid

when we have a giant covalent or ionic lattice

6.022 x 10^23 units of a substance

the amount of a solute (in g or mol) per unit volume (always dm^3)

Gas particles move rapidly and randomly. The volume of the actual gas particles is negligible compared to empty space between them. There are no intermolecular attractions or repulsions. Collisions between particles are elastic - no energy is lost. The average kinetic energy of particles depends only on their temperature.

a gas which obeys all the assumptions made in kinetic theory and can be exactrly represented using the ideal gas equation at room temp and pressure

empirical formula gives the lowest whole number ratio of elements present in a compound while the molecular formula shows the actual number of atoms of each element present in a compound

assume the total sample size is 100g find the moles of each element present by dividing the percentage by the Ar find the lowest whole number ratio of the moles

calculate the empirical formula mass then divide the molecular formula mass by the empirical formula mass multiply the ratio of atoms in the empirical formula by the resulting number