Qualifying chemistry Flashcards
How to calculate the mole?
Mass divided by molar mass
How to find the mass of a compound?
Mole multiplied by molar mass
What is avogadro’s number?
6.02 x10^23
How to fid the number of moles from the amount of atoms?
Divide the known number of atoms by avogadros number to find the mole.
How to find the number of atoms in a compound?
Multiply the number of moles by avogadros number.
How to set up the empirical formula? (5)
- write elements and %
- assume 100g sample
- divide by molar mass
- divide by smallest mass
- Therefore the EF of x compound is …
What is the formula for calculating the relative atomic mass (RAM)?
RAM= (abundance x RIM) + (abundance x RIM)
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100
How to calculate the molecular formula from the empirical formula?
Either use the molar mass or the mole of the empirical formula depending on what quantity the molecular formula has and divide them to find the ratio. then times the EF by this ratio to find the MF.
Why is carbon 12 used as a standard for the measurement of other atomic masses?
Carbon 12 has the exact measurement of 12 units so other relative isotopic masses can be found by comparing them to carbon.
What is the relative isotopic mass?
The relative isotopic mass is an isotope based on the comparison to carbon 12.
What is relative atomic mass?
The average of the relative masses of each isotope of a given element according to their percentage abundance.
What is the relative molecular mass?
The total of the relative atomic masses of elements in a formula.
What is a mass spectrometer?
Used to identify the existence of isotopes and their relative isotopic abundance so that relative atomic masses can be determined.
How does a mass spectrometer work?
Uses a magnetic field to seperate accelerated particles according to their mass and charge.
What is the mole defined as?
The number of Carbon 12 particles in 12 grams of carbon 12.
