Amount Of Substance Flashcards
What is the equation for relative atomic mass?
1/12 mass of one carbon-12 atom
what is the equation for relative molecular mass?
1/12 mass of one carbon-12molecule
what is a mole?
the amount of substance that contains 6.022 x10^23
what is the Avogadro constant formula?
no. of particles=moles x 6.022 x10^23
what is the formula for calculating moles?
mass of substance
————————— = no. of moles
molecular mass
what are the units for concentration?
moldm-3
how do you calculate moles using concentration?
concentration x volume(dm3)
how do you convert cm3 to dm3?
cm3\1000
what does the ideal gas equation allow you to find
the no.of moles in a certain volume at any temperature and pressure.
what does pV=nRT stand for?
p=pressure(pa) v=volume n=no.moles r=gas constant(8.31klmol-1) t=temperature in k
how do you convert kpa to pa?
kpa x 1000
how to you convert degrees to kalvin?
add 273
how do you convert cm3 to m3?
cm3 x 10-6
how do you balance equations?
- write word equation
- write formulas involved
- balance from left to right
how do you write an ionic equation?
- full balanced equation
- split any dissolved ionic species into ions
- take out any ions that appear on both sides
how do you calculate how much product you get from a product?
- write out balanced equation
- workout how many moles of reactant you have
- use molar ratio to workout the number of moles of product that will be formed this much reactant
- calculate the mass of that moles of product
what is different about calculating gas volumes
once moles of product is found it is put into the ideal gas equation.
what is neutralisation?
acid reacts with an alkali you get salt and water
what is the empirical formula?
the smallest whole number ratio of atoms in a compound
what is the molecular formula?
gives the actual number of atoms in a molecule
how do you calculate empirical formula?
- turn percentages into masses
- divide each mole by the smallest one
- apply the ratio number into the formula
what is the theoretical yield?
mass of product that should be formed in a chemical reaction
how do you calculate theoretical yield?
- workout how many reactant moles
- use equation to workout how many moles you would have of product
- calculate the mass of that many moles in prodcut
how do you find the percentage yield?
actual yield
———————— x 100
theoretical yield
what is atom economy?
measure of the proportion of reactant atoms that become apart of the desired product
what are the advantages of high atom economy
more efficient use of materials means less waste
how does yield effect the economy?
produce less waste is better for economy
how do you calculate atom economy?
molecular mass of desired product
———————————————————x100
sum of all molecular masses ofreactants