A 2.00 g sample of NaHCO3(s) is heated in a 10.00 g crucible to drive off H2O and CO2. The mass data — Laboratory Chemistry Chemistry Question

A 2.00 g sample of NaHCO₃(s) is heated in a 10.00 g crucible to drive off H₂O and CO₂. The mass data in the table were collected by heating the crucible and then periodically letting it cool to room temperature and reweighing it. Which is the first measurement after which heating could have been stopped?