Jupiter has 4 main moons. Io, Calliso, Europa, Ganymede.
Io is the 3rd largest of Jupiter's moons. With a mass of 89,319,379,731,108,900,000,000 kg. Io is 421,800 km away from Jupiter. It takes Io 1.769 earth days to make a full rotation. Io is made out of molten sulfur. The most common gas on Io is sulfur dioxide.
Callisto has a mass of 1.07 x 10^23. The common gas of Callisto is carbon dioxide. It takes Callisto 16.6890184 earth days to orbit Jupiter.
Europa has a mass of 47, 998, 438, 387, 492, 700, 000, 000 kg. It takes Europa 3.551181041 earth days to make one full orbit. Europa's common mass is oxygen.