quantitative chemistry Flashcards
what is the law of conservation of mass?
matter is not created or destroyed during a chemical reaction.
what is the formula for RAM?
sum of (isotope abundance x isotope mass number) / sum of abundances of all the isotopes
define a mole
avogadros number (6.02x10^23) of an atom, ion or compound.
what is the formula to calculate moles?
moles = mass / relative formula mass
what is a limiting reagent?
a reactant that is totally used up so it determines the amount of product formed.
what is an excess reagent?
a reactant that is more than is required to react with the limiting reactant
what is theoretical yield?
the maximum amount of product that can be made
what is actual yield?
the amount of product that is made from the reaction
how do you calculate percentage yield?
percentage yield = actual yield/theoretical yield x 100
why might yield be less than 100?
reversible reaction so some of the product may have rereacted, product is lost in collection, unintentional side effects may occur
what is atom economy?
a measure of the number of atoms in the starting materials that end up as useful products
what is the formula for atom economy?
rfm of desired product/rfm of all reactants x 100
what is measured in titration?
acid needed to neutralise alkali
what is the titre?
the volume of liquid that is added
what are concordant results?
titres within 0.10cm^3 of each other
