Video Transcript
How many hydrogen atoms are there
in a molecule of methane, CH4?
This is the chemical formula for
the molecule methane. The chemical formula tells us the
type and number of atoms that are in one unit of a compound. We indicate the type of atom using
the atomic symbols for each element found on the periodic table. And we indicate the number of each
type of atom using subscripts. So, from the chemical formula CH4,
we can tell that methane must contain carbon and hydrogen.
If we look at the subscript, carbon
has no subscript. This is because, by convention, we
leave off the one in the chemical formula if there’s only one of an atom in a
compound. So, that means that there is one
carbon atom in a methane molecule. And we can see that there’s a
subscript four next to hydrogen, which means that there’s four hydrogen atoms in
methane. This question asked us how many
hydrogen atoms there are in a molecule of methane. And as we just discussed, there are
four.
