If an unknown compound is found to have an empirical formula of CH4, which of the following is the molecular formula if the molar mass was determined to be 128 g/mol?
Loading ...
Correct Answer: D. C8H32
To determine the molecular formula using an empirical formula, the ratio of the molecular mass to the empirical mass must be calculated. Dividing the molecular mass of 128 grams by the empirical mass of ~16 grams (C = 12g + H = 1g, but there are 4 hydrogens in the compound) gives you approximately 8. This indicates that the empirical subscripts must be multiplied by 8 to result in the molecular formula of the unknown compound, C8H32.
Subscribe below to get the DAT Question of the Day delivered straight to your inbox every morning.
