<![CDATA[Abstrak: Penelitian ini betujuan meningkatkan pemahaman konsep siswa pada materi persamaan reaksi melalui pembelajaran berbasis masalah dengan media diagram submikroskopik. Penelitian ini merupakan penelitian tindakan kelas yang dilaksanakan dalam dua siklus. Subjek penelitian adalah 35 siswa kelas X MIA 1 SMA Muhammadiyah 1 Pontianak. Instrumen penelitian ini adalah angket, LKS, tes hasil belajar dan lembar observasi. Pemahaman konsep siswa diukur berdasarkan hasil tes individu dan diagram submikroskopik kelompok pada setiap siklus. Hasil penelitian menunjukkan peningkatan pemahaman konsep siswa.Persentase siswa yang tuntas meningkat dari 2,94% pada pra siklus menjadi 44,12% pada siklus I dan 70,59% saat siklus II. Persentase kelompok yang dapat membuat diagram submikroskopik reaksi dengan tepat meningkat dari 42,86% saat siklus I menjadi 100% saat siklus II. Dengan demikian dapat disimpulkan bahwa pembelajaran berbasis masalah dengan media diagram submikroskopik dapat meningkatkan pemahaman konsep siswa.  Kata kunci : pemahaman konsep, pembelajaran berbasis masalah, diagram submikroskopik Absract: The aim of this study was to enhance students’ conceptual understanding at chemical equation through problem based learning using submicroscopic diagrams. This study was presented as a classroom action research which was conducted in two cycles. The subject were 35 students of X class MIA 1 at SMA Muhammadiyah 1 Pontianak. The instruments of this study were questionnaires, student whorksheets, achievment test and observation sheet. Students’ conceptual understanding were measured according to students ability in answering the achievment test and drawing summicroscopic diagrams of group at each cycle . The result shows improvement of students’ conceptual understanding. Percentage of students who master concept increased from 2,94% to 44,12% at pre cycle to first cycle and from 44,12% to 70,59% at first cycle to seceond cycle. Percentage of groups who are able to draw submicroscopic diagrams of reaction correctly increased from 42.86% to 100% at first cycle to second cycle. The conclution of this study is the problem based learning through submicroscopic diagrams media improve the students’ conceptual understanding.  Key words : conceptual understanding, problem based learning, diagrams submicroscopic]]>
