C4 Chemical Calculations Flashcards
What is a mole?
One mole is the amount of substance that contains 6.02 x 10^23 particles of that substance
What is 6.02 x 10^3 known as?
As the Avogadro Number
What is one mole of any element equal to?
One mole of any element is equal to the relative atomic mass of that element in grams.
What is the Mass, Mole, Relative Formula Mass Triangle?
Mass is at the top of the triangle
Mole and RFM are at the bottom.
What does a subscript have to do?
It has to cut the line
What does a formula show us?
It shows us the mole ratio of atoms within a substance
What does the empirical formula show us?
It shows us the simplest (whole number) mole ratio of atoms of each element present within a compound.
What does the molecular formula show us?
It shows us the actual (whole number) mole ratio of atoms of each element within a molecule.
What equipment is used to measure volume in cm^3
Volumetric Flask
What is used to measure mass/g?
Mass Balance
What happens within every measurement made?
There is always some uncertainty. We often record this as an element as a + or - value.
What is common to use in a chemical reaction involving two reactants?
It is common to use an excess (more than its needed) of one of the reactants?
Why would we use an excess in a chemical reaction involving two reactants?
It is done to ensure that all of the other reactant is used.
What is the name of the reactant that is completely used up?
It is called the limiting reactant because it limits the amounts of products
What is the formula for the percentage of mass of an element in a compound?
Uhh not sure but
% by mass of Fe in Fe2O3 = 100 x 2(56)/160 = 70%
and
% by mass of O in H2O is 16/18 x 100 = 88.9%
sooo i think its
Element Mass over Compound Mass times by 100
What is the concentration (c) of a solution?
It is the amount of substance per unit volume.
