Gas hydrate is a nonstoichiometric structure that has been produced from water and gas in appropriate thermal and pressure conditions. There has been a long time that scientists work on predicting hydrate production condition. Predicting the hydrate behavior for pure substances is easier than mixtures; because there are some behaviors of mixtures that we do not know their reasons yet. In this thesis, there has been tried to give a model to describe hydrate reactions to temperature and pressure changes besides predicting the hydrate type and the cage occupancy. Since the hydrate behavior is nonstoichiometric, it is useful to know the cage occupancy to predict the amount of hydrate...