Chemical calculations Flashcards
what is a theoretical yield?
the maximum possible mass of a product that can be made in a chemical reaction.
what is the actual yield?
the mass of a product actually obtained from the reaction.
explain why the actual yield is often lower than the theoretical yield (3)
-incomplete reactions, in which some of the reactants do not react to form the product
-practical losses during the experiment, such as during pouring or filtering
-side reactions (unwanted reactions that compete with the desired reaction)
equation for percentage yield:
(actual yield/ theoretical yield) x100
what is the atom economy of a reaction?
a measure of how many reactant atoms form a desired product.
equation of atom economy:
(total Mr of desired product/ total Mr of all reactants) x100
What does a lower atom economy imply?
there were more unwanted by-products in the reaction
how can the atom economy of a particular reaction can be improved? (2)
by finding a use for the by-product, by making it another desired product.
Sometimes, the by-product can be sold for additional profit.
what does avogadro’s law state?
equal volumes of different gases contain an equal number of molecules.
what is the molar volume?
the volume occupied by one mole of any gas, at room temperature and pressure.
equation for the volume of gases:
volume = moles x 24 dm^3
