Video Transcript
Fill in the blank. The number of carbon atoms in an alkene containing 10 hydrogen atoms is blank.
An alkene is an unsaturated hydrocarbon that contains at least one carbon-carbon double bond. Alkenes that contain only one carbon-carbon double bond have the general formula C𝑛H2𝑛, where 𝑛 represents the number of carbon atoms in the molecule. The alkene in the question contains 10 hydrogen atoms. And we need to determine the number of carbon atoms the molecule contains. From the general formula, we can see that the number of hydrogen atoms an alkene contains must be equal to two times 𝑛. This means we can set up the equation two times 𝑛 equals 10. We can divide both sides of the equation by two to determine that 𝑛 is equal to five.
As 𝑛 represents the number of carbon atoms in the alkene, we now know that this alkene must contain five carbon atoms. To verify that this is correct, let’s draw a possible structure for this molecule. We know that the molecule must contain five carbon atoms. And since the molecule is an alkene, two of these carbon atoms must be joined by a carbon-carbon double bond. Each carbon atom must form a total of four covalent bonds. And since an alkene is a hydrocarbon and all five carbon atoms are already accounted for, these bonds must be between carbon and hydrogen atoms.
We can see from the structure that an alkene containing 10 hydrogen atoms contains five carbon atoms. So, we should fill in the blank with five carbon atoms.
