At which stage does a gas form in a gas formation reaction

How will the emission of an alpha particle affect the atomic number of an atom

In which environment would primary succession occur? a forest with a few remaining trees after a recent wildfire an area of exposed rock after a glacier melts away beach that is exposed to the air at low tide an abandoned baseball field in a small town

How would the number of moles (n) of o2 change if the atmospheric pressure doubled but all other variables stayed the same