to be in kg/mL. What you need to do first is write 22.4 kg/L over 1. Divide this by 1000 because there are 1000 mL per L. Your equation will look like 22.4 kg/L over 1 divided by 1000/1. You end up getting .0224 kg/mL.
The first bond between two atoms is always a sigma bond and the other bonds are always pi bonds and a hybridized orbital cannot be involved in a pi bond. Thus we need to leave one electron (in case of Carbon double bond) to let the Carbon have the second bond as a pi bond.
It may be unreliable because it might mess something up from the speed.