Stoichiometry Flashcards
Molecular formula
The number and type of different atoms in one molecule
What does each formulas tell us?
Molecular
Structural
Empirical
The molecular formula chose you the actual number of atoms of each element in one molecule of the compound or element. The structural formula tells you the way in which the atoms in a particular molecule are bonded. The empirical formula is the simplest ratio of the atoms of each element present in one molecule or formula unit of the compound.
Empirical formula
Formula that shows the simplest whole number ratio of the atoms of each element present in one molecule or formula unit of the compound. ionic compound is always an empirical formula
Relative atomic mass
The average mass of the isotopes of an element compound to 1/12th of the mass of an atom of C12
Relative molecular mass (Mr)
The total mass of the molecule.
Molar mass
The mass of one more of a substance for an element it’s the same as AR and for compound is the same as MR in grams
The mole & Avogadro constant
The more is the SI unit of amount of substance one more of a substance contain in the same number of the stated particles atoms molecules or iron as one more of any other substance one more equals 6.02 x 10^23
Volume of gas formula
Volume(dm^3) = mole x 24
Mass formula
Mass = mole x Mr
Finding the reacting masses
- Information given in the question is used to find the amount in moles of the substance being considered.
- The ratio between the substances is determine using balance in both equation
- Once the moles has been determined they can be converted into grams or mass using the AR or Mr
Limiting reactants
The chemical or reactant that is used at first in a chemical reaction which stops the duration of the reaction
Steps of calculating limiting reactants
Write the balance equation for the reaction how can let them most of each reactants compare and deduce the limiting reactant
Concentration formula
Moles = concentration x volume
Mol/dm^3
Cm cube to dm cube
Cm to dm /1000
Dm to cm x1000
G/dm^3 to mol/dm^3
/Mr
XMr
Convert empirical formula to molecular formula
Mr of molecular formula/ Mr of empirical formula
% yield
Used to describe the amount of product from a reaction
Why is percentage yield never 100%
Reactants being left behind in the equipment
some products may be lost during separation purification stages
side reactions when a substance react with a gas in the air or an imparity in one of the reactants
loss of product during transfer from one container to another
Percentage yield formula
Actual yield/theoretical yield x100
Theoretical yield
The amount of product that would be obtained under perfect practical and chemical conditions
Actual yield
The recorded amount of product obtained
Percentage mass
Finding the percentage by mass of a element within a compound
% mass
Total mass of the element in a compound/MR of the compound x100
% purity
Used to calculate how pure the substance is with nothing else mix with it however the product can become contaminated with unnamed substances and impurities
Percentage purity formula
Mass of pure substance/total mass of substance x100
