Determining the molecular formula of a hydrocarbon with a relative molecular mass of 54​

C₄H₆

Explanation:

A hydrocarbon is a molecule that only contains atoms of Carbon and Hydrogen. As you remember, the molar mass of Carbon is 12g/mol and the molar mass of Hydrogen is 1g/mol.

To solve this question we can find the amount of Carbons necessary that doesn't exceed the 54g/mol. That is:

54g/mol / 12g/mol = 4.5

As the molecular formula must be given in whole numbers, the amount of Carbons is 4. This 4 carbons have a mass of:

12g/mol*4 = 48g/mol

And the hydrogens necessaries to suply the molecular mass are:

54 - 48 = 6 hydrogens

That means molecular formula is:

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.