KETERAMPILAN BERPENDAPAT SISWA KELAS XI SMA MELALUI PENERAPAN METODE PROBLEM SOLVING PADA MATERI LAJU REAKSI (STUDENT’S ARGUMENTATION SKILL IN XI GRADE WITH IMPLEMENTATION OF PROBLEM SOLVING METHOD ON REACTION RATE MATTER) - RANDI ASHARI, VANANTIA (UNESA Journal of Chemical Education, 2015)