Amount of Substance (3.1.2-Phys.) Flashcards
Define relative atomic mass
Average mass of an atom compared to 1/12th the mass of an atom of carbon-12.
Define molecular mass
Average mass of a molecule compared to 1/12th the mass of an atom of carbon-12.
Define relative isotopic mass
Mass of an isotope compared to 1/12th the mass of an atom of carbon-12
What is the Avogadro constant?
6.022 x10^23
How do you calculate the number of particles using the Avogadro constant?
Moles(mass/rfm) x Avogadro number
How do calculate mass using the Avogadro number?
[molecules / Avogadro no.] x RFM
What is the ideal gas equation?
pV = nRT
What are the units of each component in the ideal gas equation?
- p, pressure = Pa
- V, volume = m ^cubed
- n, moles
- R (given)
- T, temp = K
How many degrees Celsius is 0K ?
-273C
How do you calculate atom economy?
(RFM of desires product x 100) / (Total RFM of products)
How do you calculate percentage yield?
(Experimental mass/ Theoretical mass) x 100
How do you calculate concentration (mol/dm^3)
moles / volume[dm^3]
How do you calculate reacting masses?
1) find moles of known
2) mole ratio
3) moles of unknown
Define ‘empirical formula’
The simplest whole number ratio of each atom in a compound
What do you include in your table of calculations when working out empirical formula?
For each element:
- mass (g) or %
- moles
- divide by smaller number
- e.f.
