2P-Amount Of Substance Flashcards
What’s relative atomic mass (Ar)
Weighted average mass of an atom of an element, taking into account isotopes, relative to the mass of 1/12 of carbon 12
What’s relative molecular mass (Mr) or molar mass
The sum of the relative atomic masses of the atoms in a molecule
How to convert from cm^3 to dm^3
Divide by 1000
Equation to calculate number of moles
Moles=mass/Mr
Equation to calculate concentration
Conc=mol/vol
Conc=mass/vol
What’s the ideal gas equation
PV=nRT
P= Pressure (Pa)
V= Volume (M^3)
n= Moles
R= Gas constant J/Kj/mol
T= Temperature (K)
How to convert from cm^3 to M^3
Dive by 10^6
How to convert from °C to K
Add 273
What’s absolute uncertainty
The true numerical value, indicates a range where the true value is
What’s percentage uncertainty
Uncertainty is expressed as a proportion of the measurement
Allows total uncertainty to be found when multiple variables are used
Equation for % uncertainty for readings
Error/ measurement then x100 to get percentage
What’s a measurement
Value taken as the difference between two values e.g change in temp
Equation for % uncertainty for measurements
(Error 1 + error 2)/measurement x 100
What’s empirical formula
The simplest whole number ratio of the atoms of each element present in a compound
Equation for atom economy
Mr of desired product/ Mr of reactants
Equation for % yield
Actual yield/ theoretical yield x 100 Actual yield is the smaller number
How to determine the error of a value
Half the smallest unit
27.2 —> 0.2/2 —> + or - 0.1
Ammonium
NH4 +
Ammonia
NH3
Carbonate
CO3 2-
Hydroxide
OH -
Nitrate
NO3 -
Nitrite
NO2 -
Sulphite
SO3 2-
Sulphate
SO4 2-
Peroxide
O2 2-
Phosphate
Po4 3-
Hydrogen carbonate
HCO3 -
Sulphuric acid
HSO4 -
Can sodium and potassium nitrates thermally decompose and if so into what
Yes
Form nitrite and oxygen
Calcium,magnesium,aluminium,zinc,iron,lead,copper (metals between sodium and silver in the reactivity series)
Nitrates
Carbonates
Hydroxides
Decompose into what
Metal Nitrate—> metal oxide + nitrogen dioxide + oxygen
Metal carbonate—> metal oxide + carbon dioxide
Metal hydroxide—> metal oxide + water
Silver and gold
Nitrates
Carbonates
Hydroxides
Thermally decompose into what
Nitrates—> metal + nitrogen dioxide + oxygen
Carbonates—> metal + carbon dioxide + oxygen
Hydroxides—> metal + oxygen + water
Why is a high atom economy advantageous for society and industry
Ethical/Econ- little waste, viable for industrial scale manufacturing
Enviro- less natural recourses used
