Solids always have definite shape and definite volume because their particles are packed together. Liquids have a definite volume but not definite shape, because their particles still kinda tight but able to move around, and gases don’t have a definite shape nor volume, because their particles are crazy and go everywhere
They are about 4.5 billion years old. Hope this helps.
The ideal gas law is P1V1/T1 = P2V2/T2. STP means the temperature is 273 K and pressure is 101.3 kPa. According to this formula, the new volume V2=2.15*58*273/(298*101.3) = 1.13 L.