Empirical Formula
What is Empirical Formula?
a formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms
What is molecular formula?
a formula giving the number of atoms of each of the elements present in one molecule of a specific compound.
__ As + __ NaOH → __ Na
2 As + 6 NaOH → 2 Na3AsO3 + 3 H2
List 2 types of chemical equations.
Combination, Combustion, Decomposition, Single Replacement, Double Replacement
1. See if it's a ionic or molecular compound.
2. Add -ide to the end of the second compounds name.
3. See if it needs prefixes
See if you need roman numerals.
88.8% Copper 11.2% Oxygen
Cu2O
Solve the molecular formula.
2(C3H3O)
C6H6O2
Li + H3PO4 ---> H2 + Li3PO4
6Li + 2H3PO4 ---> 3H2 + 2Li3PO4
What is the type of reaction?
8Fe+ S8 -----> 8FeS
Combination
Li2S
Lithium Sulfide
How do you find the Empirical Formula of a compound?
Convert the mass, divide each mole, and round to whole number.
A hydrocarbon is a compound comprised of carbon and hydrogen atoms. An unknown hydrocarbon is found to contain 85.7 percent carbon and an atomic mass of 84.0 g/mol. What is its molecular formula?
C6H12
ZnS + O2 ---> ZnO + SO2
2ZnS + 3O2 ---> 2ZnO + 2SO2
"One element being displaced from a compound by another element..." this is describing which type of chemical equation?
Single
MgBr2
Magnesium Bromide
An atom or group of atoms having a electric charge
Ion
A piece of iron ore is found to contain a compound containing 72.3 percent iron and 27.7 percent oxygen with a molecular mass of 231.4 g/mol. What is the molecular formula of the compound?
Fe3O4
FeS2 + Cl2 ---> FeCl3 + S2Cl2
2FeS2 + 5Cl2 ---> 2FeCl3 + 2S2Cl2
What type of chemical equation is Na2S + HCl -----> NaCl + H2S
Double Replacement
Cr3(PO4)2
Chromium (ll) Phosphate
A compound is found to contain 23.3% magnesium, 30.7% sulfur and 46.0% oxygen.
What is the empirical formula of this compound?
MgSO3
A compound containing 40.0 percent carbon, 5.7 percent hydrogen and 53.3 percent oxygen has an atomic mass of 175 g/mol. What is the molecular formula?
C6H12O6
Fe2O3(s) + C(s) ---> Fe(s) + CO2(g)
2Fe2O3(s) + 3C(s) ---> 4Fe(s) + 3CO2(g)
What type of chemical equation 2Ni2O3 ---> 4Ni + 3O2
Decomposition
KI
Potassium Iodide