unit 1 section 2 Amount of Substance Flashcards
what is Avogadros constant
6.022x10^23
how to work out the number of particles
number of particles = moles x avogadros
what is the equation for the ideal gas equation
P x V = N x R x T
p = pressure (pa )
v = volume ( m^3)
n= number of moles
r = gas constant ( 8.31)
t = temperature ( k )
how do you convert Kpa to pa
x 1000
how do you convert degrees into kelvin
you add 273
how do you convert cm^3 to m^3
divide by 10^6 or you times it by 10^-6
how do you convert dm^3 to cm^3
x10^3
how do you write ionic equations
first you write the full balanced equation and then you split it up into their ions and you remove any ions that appear on both sides.
what do you get when an acid reacts with a alkali
salt + water
what is a standard solution
it is any solution you know the concentration of
how do you make a standard solution
you dissolve a known amount of solid into a know amount of water
how to carry out a titration
1 - pipette a set volume of solution you want to know the concentration of. and add a few drops of indicator
2- fill up the burette with a standard solution of acid, you a funnel to pour in acid.
3- then you do a rough titration to get an idea of the end point of the reaction.
4- then you do an accurate titration, run acid within 2cm^3 of end point and then add acid dropwise while swirling the solution until the solution is neutralised and work out the titre by subtraction the final reading by the initial reading.
5- repeat the test a few times until you have at least 3 concordant results.
what are concordant results
they are results that are within 0.1 cm^3 of each other
what is empirical formula
it is the smallest whole number ratio of atoms of each element in a compound
what is the molecular formula
it is the actual number of atoms in a molecule.
how to calculate molecular formula from the empirical formula and mr
1- find the empirical mass(mr) of the compound.
2- divide the mr by the empirical mr
3- multiply the empirical formula by the number you got.
how do you work out the empirical formula for the percentages of the elements present
1- assume 100g of compound, work out the moles of each element with the percentages as grams.
2 - divide each number of moles by the smallest number of moles you find in step 1
3- apply those number to the formula ( numbers must be whole numbers )
what is the theoretical yield
it is the mass of a product that should be formed in a chemical reaction.
what is the actual yield
it is the mass of product that is produced in the reaction.
what is the equation for percentage yield
percentage yield = actual yield / theoretical yield x100
what is atom economy
it is the measure of the proportion of reactant atoms that become part of the desired products in the balanced chemical equation
what are the economic advantages of high atom economy
- company has more efficient use of raw materials
- company will have less waste to deal with , means less money is spent on disposing waste safely and less time is spent separating desired product from waste product.
what are the environmental and ethical advantages of using high atom economy
- limited supply of raw materials , means they last longer when used efficiently
- less waste - less harmful chemicals which are difficult to dispose.
- more sustainable
what is the equation for atom economy
atom economy = molecular mass of desired product / total molecular mass of reactants x 100
how do you convert mPa to Pa
x1,000,000
x 1 million
