CALCULATIONS Flashcards
define mole
The amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12
Define relative atomic mass
The average mass of one atom compared to one twelfth of the mass of one atom of carbon 12
Define relative molecular mass
The average mass of a molecule compared to one twelfth of the mass of one atom of carbon 12
What is Avogadro’s number
6.022 x 10 ^23
Three mole calculations
Moles = mass/mr
Pressure x Volume = Moles x Constant x Temperature
Moles = concentration x volume
What is the gas constant
8.31
What are the units for the gas equation
Pressure : pascals
Volume : m3
Temperature : kelvin
How do you convert volumes
Cm3/1000 = dm3
Cm3/1,000,000 = m3
Dm3/1000 = m3
How do you temperature
C + 273 = K
How many significant figures should things be given to?
Same as the data in the question unless stated otherwise
Or the smallest used in the question
Outline the Avogadro’s constant equation
Number of particles = moles x Avogadro’s constant
6.022 x10^23
What is the density equation
Density = mass/volume
Define empirical formula
Simplest ratio of atoms of each element in the compound
Outline the general method for calculating empire lie formula
1) divide each mass by atomic mass
2) Divide each answer by the smallest
(3) multiply to get whole numbers)
Define molecular formula
The actual number of atoms of each element in the compound
Outline how molecular formula is calculated from the empirical formula
Calculate the atomic mass
Mr/atomic mass
Convert ratios
How do you balance an ionic equation
Atoms and charges must be balanced
To have the same total charge either side
How do you convert mol dm-3 into g dm-3
Multiply the concentration by the substances mr
gDm-3 = mol dm-3 x Mr
What is the percentage yield equation
Percentage yield =
Actual yield / theoretical yield
X100
What is the atom economy equation
Percentage atom economy =
Mass of useful product / mass of all reactants
x100
define mole
The amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12
Define relative atomic mass
The average mass of one atom compared to one twelfth of the mass of one atom of carbon 12
Define relative molecular mass
The average mass of a molecule compared to one twelfth of the mass of one atom of carbon 12
What is Avogadro’s number
6.022 x 10 ^23
