If your bike isn't the right size, your legs could be rubbing up against the seat of your bike. The friction can chafe the skin on your legs. If you were to crash your bike, skidding on the ground can cause anywhere from minor scrapes to serious friction burns.
Amount of NH3 = 6.39 mol
Ratio of NH3 : Ratio of product
4 : 10
Hence, amount of product formed = 6.39/4 * 10 = 15.975mol = 16.0mol (3sf)
