Muscle cramps may be brought on by many conditions or activities, such as: 1  Exercising, injury, or overuse of muscles. 2  Pregnancy. Cramps may occur because of decreased amounts of minerals, such as calcium and magnesium, especially in the later months of pregnancy.  Exposure to cold temperatures, especially to cold water.
Butane is a colorless gas with a faint petroleum-like odor. For transportation it may be stenched. It is shipped as a liquefied gas under its vapor pressure. Contact with the liquid can cause frostbite.
1 gaseous butane escapes. 2  liquid butane evaporates to ensure the equilibrium of the vapour pressure. 3  the remaining liquid butane is cooled by the need to transfer the enthalpy of vapourization to the butane which evaporates.  this loss of heat is compensated by heat from the enviroment (eg, a smoker's hand)