Hi, I'm Robin Higgins, and this is the molecular formula for an alkane molecule. So let's define what an alkane is. Well, an alkane is a functional group name, and it can be used for something that has carbons and hydrogens and only single bonds. So this is an alkane. And so remember that if it has a double bond, it's called an alkene, if it has a triple bond it's called an alkyne. So, our alkanes just have single bonds. Now, if we draw it out fully with all the carbons and hydrogens showing, we can get the chemical formula. And so remember these are the same things, just drawn a little differently. So, let's count up how many carbons and hydrogens we have. Well, we have four carbons, and we have one, two, three, four, five, six, seven, eight, nine, ten, hydrogens. So, this is our chemical formula. Let's do a couple other ones. So, if we just have one carbon with all hydrogen attachments, this is also an alkane, this is actually called methane. It's the simplest alkane you can get. And its formula is CH4. But they don't just have to be in a straight line. They can also be cyclical. So, let's say we had this guy, if we draw him out, you get this, and each carbon is gonna have two hydrogens, this is called cyclopentane, we have five carbons, and we have two hydrogens on all of those carbons. So, our chemical formula is C5H10. I'm Robin Higgins, and this is what is the chemical formula of an alkane.