chemical calculations Flashcards
ehat is the law of conservation of mass
a law that states that no atoms are lost or made dyring a chemical reaction, so the mass of the products equal the mass of the reactants
what is relative formula mass
it is the sum of the relative atomic masses of the atoms in the molecule
why do some reactions appear to increase in mass
when substances react with gases in the air such as oxygen the mass will increase
why so some reactions apprar ton decrease in mass
when a gas is a product in a chemical reaction and it is released into the atmosphere
how do you calculate uncertainty
calculate the range im results and divide by 2
what are the chemical amounts measure in
moles
what is the units for moles
mol
what is the value of the avogrado constant
6.02x10 to the power of 23
what is a limiting reagent
it is the reactant that is completely used up that limits the amount of products
what are the units for concentration
mass per given volume
why is it not always possible to obtain the calculate amount of product
the reaction may not go your way completion because its reversible, some of the product may be lost when it is seperated from the reaction mixture or some of the reactants may react in ways different to the expected reaction
what is yield
the anount of product obtained in a reaction
how can yield be calculated
% yield= (mass of product/ theoretical mass) x100
what is an atom economy
a measure or the amount of starting materials that end up as useful products
why is it important to use reactions with high atom economoy
for substainable development
