3.2 Stoichiometry Flashcards
What is relative atomic mass and symbol
The average mass of the isotopes of an element compared to 1/12 the mass of an atom of carbon - 12
What is relative molecular Mass + symbol
The sum of the relative atomic masses in a molecule
Mr
What is relative formula mass
The sum of relative atomic masses in ionic compounds
What is avagadro’s number+symbol
6.02x10^23
NA
“Law” about concentration
The greater the amount of solute in a given volume(solvent) the greater the concentration
Concentration formula + units
c=n/v
g/dm3
(G/dm3=mol/dm3 x MR
“Law” of volume of gas
One mole of any gas occupies a volume of 24 dm3
What is a compound
A substance formed by the union of two or more elements.
What is the law of conservation of mass
No atoms are lost or made in a chemical reaction, the atoms join together in different ways to form products
Percentage yield formula
Actual yield/theoretical yield x 100
Empirical formula of a compound
The simplest whole number ratio of the different atoms or ions in a compound
molecular formula of a compound
Actual number for each type of atom in a compound
Number and type of different atoms in one molecule
Percentage purity formula
(Atomic mass x number of mols of particular element in a compound)/molar mass of a compound x 100
Concentration of a solution
Amount of solute dissolved in a solvent to make 1 dm3 of solution, the greater the amount of solute in a given volume, the greater the concentration.
Concentration units
Mol/dm3
How to convert from cm3 to dm3
Divide by 1000
Room pressure
1 atm
Volume of gas formula
V=n x 24
Mass formula
m=n x M
Molar mass unit
g/mol
How to find molecular mass
Calculate the molar mass of the empirical formula
Relative molecular mass is divided by your answer
Multiply each elemnt in the empirical formula to get the answer
How to find empirical formula
Change % into grams
Find number of mols
Divide each of the mols by the smallest number of mols
Times by the same whole numbers if you dont end up with whole numbers
How can we ensure that we have the most amount of product in a reaction
When the product is produced in excess
Limiting reagents
Limits amount of product formed
The mole
Mass of a substance containing the same number of atoms/ions/molecules as there are in exactly 12.00g of 12carbon
Covalent bond
Compounds formed when electrons are shared between atoms that are non-metal
Define molecular formula of a compound
The number and type of different atoms in one molecule
Define empirical formula of a compound
The simplest whole number ratio of the different atoms and ions in a compound
What can concentration be measured in
g/dm3 or mol/dm3 (divide by mr)
