The research aim to determine the improvement critical thingking ability student’s on the subject of thermochemistry in implementation of Process Oriented Guided Inquiry Learning (POGIL) strategy at 11Th grade SMA Negeri 8 Pekanbaru. The research is experimental research with One Group Pretest Posttest Design which in hield in SMA Negeri 8 Pekanbaru at academy years of 2017/2018. The object o…