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.
The difference between empirical and molecular formulas can be illustrated with butane, a covalent compound used as the fuel in disposable lighters. The molecular formula for butane is C 4 H 10. The ratio of carbon atoms to hydrogen atoms in butane is 4:10, which can be reduced to 2:5.