Final answer:
Dividing the number of hydrogen atoms by the number of carbon atoms gives you the H:C ratio of a compound, which can be used to determine the molecular or empirical formula, particularly after normalizing non-integer ratios to whole numbers.
Step-by-step explanation:
When you divide the number of hydrogen atoms by the number of carbon atoms, you are calculating a ratio that can provide insight into the molecular structure of a compound.
The method of normalization is often used when these numbers are not integers to get a simple whole number ratio that can help determine the empirical formula of a compound.
For instance, if the relative molar amount of hydrogen is given as 1.333 and carbon as 1.0, multiplying both by 3 (to normalize) would result in 4 atoms of hydrogen and 3 atoms of carbon, typically expressed as H:C = 4:3.
In a balanced chemical equation, you can use the coefficients directly to obtain this ratio. For example, if we balance a hydrocarbon compound like octane (C8H18), we can discern the H:C ratio directly from the balanced molecular formula which would be 18:8 or simplified 9:4.
Another aspect to consider is the stoichiometric formula used in carbohydrates, (CH2O)n, showing a ratio of 1:2:1 for C:H:O.
Understanding Empirical Formulas
Using experimental data, such as the number of moles of each element present, you can divide by the smallest amount to find the simplest whole number ratio formula for the compound.
This is demonstrated in the empirical formula for propanol where the number of moles of carbon (0.0128), hydrogen (0.0340), and oxygen (0.0042) are normalized to yield C3H8O, within experimental error.