Chapter 3 Amount of Substance Flashcards
What is the Avagadros constant?
6.02 x 10 ^23
What is the equation to work out the number of moles given a mass?
Moles = Mass/Mr
The RAM in (g) of an element =
6.02 x 10 ^23
What is the molar mass?
The mass in grams in each mole of the substance UNIT: g mol -1
The RAM or RMM (in g) =
1 mole of a substance = MOLAR MASS
A standard solution is a solution of __________
KNOWN CONCENTRATION
What is the empirical formula?
the simplest ratio of the atoms of each element in a compound
What is the molecular formula?
the actual number of atoms of each element in the compound
What is the water of crystallization?
The water in a lattice
A solid salt which contains water of crystallization is a?
Hydrated salt
A salt that doesn’t contain water is a?
Anhydrous salt
What is the relative molecular mass?
is the average mass of a molecule compared to 1/12th of the mass of one atom of carbon-12
What is the relative formula mass?
Compares the mass of a formula unit with the mass of an atom of carbon-12.
What is the water of crystallization experiment?
1) Weigh an empty clean, dry crucible and lid
2) Add 2g of hydrated salt into the weighted crucible
3) Weigh the crucible and the hydrated salt
4) Use a pipe clay traingle, support the crucible containing the hydrated salt on a tripod
5) Heat the crucible and contents gently for 1 minute
6) Then heat it strongly for a further three minutes
7) Leave the crucible to cool. Then weigh the crucible and anhydrous salt.
What is the formula to find out the moles in a solution?
n = vol x conc
—————–
1000
