Explanations:
Percentage composition of a compound is the percentage by mass of each element presents in a compound. For instance is the percent by weight of the elements in a compound are given in percentage, they can be converted to masses.
These masses are converted to moles and its simplest multiple ratio is useful in determining the empirical formula of the molecule. The empirical formula is simply the simplest whole number ratio of atoms present in a compound.
The significance of empirical formula is that it helps us to determine the numbers and types of atoms composing a single molecule of the substance;
For instance, if a compound contains 5g of carbon, 2g of hydrogen and 12 grams of oxygen, the empirical formula is calculated using the steps below:
Step 1: Calculate the moles of the element
Mole = mass/molar mass
Moles of C = 5/12 = 0.42moles
Moles of H = 2/1 = 2moles
Moles of O = 12/16 = 0.75 moles
Step 2: Divide by the simplest mole ratio
For Carbon: 0.42/0.42 = 1(5) = 5
For hydrogen: 2/0.42 = 4.76(5) = 24
For Oxygen: 0.75/0.42 = 1.79(5) = 9
This shows that the empirical formula is C5H24O9
The general chemical reaction is expressed as:
