A comet
None. It is too cold to have any gasses. The surface appears to be methane frozen into solid methane.
It is mostly made of rock and frozen methane.
Because of the planets extremely cold temperature. The "ice" is frozen methane ice.
No. While frozen methane, carbon dioxide, and nitrogen do exist on Pluto, they are not metals.
A space object formed from dust and rock particles mixed with frozen water, methane, and ammonia that forms a bright coma as it approaches the sun is a comet.
Sedna is a trans-Neptunian object with a composition of rock and ices, likely including water, methane, and nitrogen. It is expected to have a surface layer composed mostly of frozen volatiles, such as methane and water ice, with a possible rocky core. The exact structure of Sedna's interior and exterior layers is still uncertain due to limited observational data.
No, Jupiter does not have mountains. It is a gas giant, and has no real solid surface. Simply put, it is a very large and cold ball of gas, with traces of frozen methane, water, Carbon dioxide on the surface.
ice.astronemers think it is frozen methane.
Eris' atmosphere is primarily composed of nitrogen, with trace amounts of methane and possibly other hydrocarbons. It is a thin and cold atmosphere, keeping the dwarf planet's surface largely frozen and inhospitable.
Pluto is composed primarily of ice and rock, with a thin atmosphere made up of nitrogen, methane, and carbon monoxide. It has a rocky core surrounded by a mantle of water ice and a surface covered in frozen nitrogen and methane. Pluto's composition is similar to that of other dwarf planets in the Kuiper Belt, where it resides.
No, the surface of Pluto is not mostly nitrogen. It consists of mostly nitrogen ice, but also contains other elements such as methane and carbon monoxide.
The planet appears to be partly covered with frozen methane gas and to have a thin atmosphere composed mostly of methane.