PENGEMBANGAN LEMBAR KEGIATAN SISWA (LKS) BERORIENTASI GUIDED INQUIRY UNTUK MELATIHKAN KETERAMPILAN PROSES SAINS SISWA PADA MATERI LAJU REAKSI KELAS XI SMA (DEVELOPMENT OF STUDENT ACTIVITY SHEET ORIENTED GUIDED INQUIRY TO PRACTICE SCIENCE PROCESS SKILLS ON REACTION RATE SUBJECT FOR ELEVENTH-GRADE SENIOR HIGH SCHOOL STUDENT)

Penelitian ini bertujuan mendeskripsikan kelayakan LKS yang dikembangkan, mendeskripsikan hasil belajar siswa, melatihkan keterampilan proses sains, dan mendeskripsikan respon siswa. Lembar kegiatan siswa termasuk dalam bahan ajar cetak (printed) yang berupa  lembaran-lembaran yang berisi tugas yang harus dikerjakan oleh siswa.LKS berorientasi Guided Inquiry merupakan LKS yang disusun berdasarkan fase-fase model pembelajaran Guided Inquiryuntuk melatihkan Keterampilan Proses Sains (KPS) siswa. KPS yang dilatihkan dalam penelitian ini yaitu merancang penelitian ilmiah, melakukan penelitian, melakukan pengumpulan data, menganalisis data, serta menarik kesimpulan. Kriteria kelayakan terdiri atas isi, penyajian, kebahasaan, dan kegrafikan. Jenis penelitian adalah pengembangan dengan metode Research and Development (R&D). Subjek penelitian adalah LKS yang dikembangkan. Instrumen penelitian terdiri atas lembar telaah, lembar validasi, lembar tespemahaman konsep, lembar tes keterampilan proses sains, dan lembar angket respon siswa. Sumber data diperoleh dari dosen kimia, guru kimia, dan 12 orang siswa Kelas XI SMA Gedangan Sidoarjo. Data dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa LKS layak digunakan sebagai media pembelajaran dengan persentase kelayakan 66,7%-100%. LKS dapat melatihkan keterampilan proses sains merancang penelitian, melakukan penelitian, melakukan pengumpulan data, membuat kesimpulan dengan sangat baik, dan keterampilan menganalisis data dengan baik. Rata-rata nilai post-test siswa pada materi laju reaksi telah melampaui nilai KKM yaitu 77,4 sehingga siswa dikatakan tuntas. Hasil respon siswa menunjukkan bahwa LKS mendapatkan respon yang positif karena memperoleh persentase 75%-100%. Kata Kunci: LKS, guided inquiry, keterampilan proses sains, laju reaksi. This aim of this study are to describe the feasibility of student activity sheet that has been developed, to describe the student learning outcomes, to practice the science process skills and to describe the student responses. Student activity sheet is printed teaching media in the form of sheets that contains tasks which must be done by students. Guided Inquiry-oriented student activity sheet is a student activity sheet based on the phases of Guided Inquiry teaching models to practice student’s science process skills. Science process skills which practiced in this study are designing scientific investigation, conducting scientific investigation, collecting and recording data, analyzing data and making conclusion. The criteria of feasibility consists of content, presentation, linguistic and graphic. The type of this study is development with Research and Development (R & D) method. The subject in this study is student activity sheet that developed. The instruments of this study consist of study sheet, validation sheet, understanding-of-concepts-test sheet, science-process-skills-test sheet, and student-questionnaire-responses sheet. Source of data was obtained from chemistry lecturer, chemistry teacher, and 12 eleventh-grade students of Gedangan Senior High School in Sidoarjo. Data is analyzed descriptively. The results showed that student activity sheet is very suitable to be used as a learning media with feasibility percentage 66,7%-100%.  The student activity sheet is able to practice the science process skills in designing investigation, conducting investigation, collecting and recording, making conclusion very well and analyzing data well. The average value of post-test on reaction rate subject had exceeded the standard score is 77.4, so students mastery learning. The result of student responses indicate that student activity sheet got positive responses with percentage of 75%-100%. Keywords: students activity sheet, guided inquiry, science process skills, reaction rat