Forming a chemical bond releases energy and therefore is an exothermic process. Exothermic reactions usually feel hot because it is giving heat to you. Endothermic-a process or reaction that absorbs energy in the form of heat. Breaking a chemical bond requires energy and therefore is Endothermic.
karma level 71199. The Seikan Tunnel is a 53.85 km (33.46 mi) railway tunnel in Japan, with a 23.3-kilometre (14.5 mi) long portion under the seabed. Track level is about 140-metre (460 ft) below seabed and 240-metre (790 ft) below sea level. It is the longest undersea tunnel in the world, although the Channel Tunnel between the United Kingdom and France has a longer under-sea portion.
By REUTERS on Publish Date June 1, 2016. Photo by Laurent Gillieron/European Pressphoto Agency. LONDON â The worldâs longest and deepest rail tunnel opened in Switzerland on Wednesday, nearly seven decades after it was first proposed and 17 years after construction began with a blast in the main shaft.