ABSTRAK
Penelitian ini bertujuan untuk meningkatkan: 1). keaktifan belajar siswa kelas X IPA 5 pada materi konsep mol dan perhitungan kimia di SMA Negeri 2 Surakarta Tahun Ajaran 2013/2014, 2). prestasi belajar siswa kelas X IPA 5 pada materi konsep mol dan perhitungan kimia di SMA Negeri 2 Surakarta Tahun Ajaran 2013/2014.
Penelitian ini merupakan Penelitian Tindakan Kelas (PTK) yang terdiri dari dua siklus. Setiap siklus terdapat empat tahapan yang terdiri dari perencanaan tindakan, pelaksanaan tindakan, observasi, refleksi. Subyek penelitian adalah siswa kelas X IPA 5 SMA Negeri 2 Surakarta Tahun Ajaran 2013/2014 yang berjumlah 32 siswa. Sumber data berasal dari guru dan siswa. Data penelitian yang diperoleh berupa keaktifan siswa (visual activities, oral activities, listening activities, dan writing activities) dan prestasi belajar (aspek kognitif dan aspek sikap). Pengumpulan data adalah dengan metode tes (tertulis) dan non tes (observasi, wawancara, kajian dokumen, angket). Teknik analisis data penelitian secara deskriptif kualitatif dan kuantitatif.
Berdasarkan hasil dari penelitian yang telah dilakukan, maka dapat diambil kesimpulan sebagai berikut: 1). penerapan Model Problem Based Learning (PBL) dengan penilaian portofolio dapat meningkatkan keaktifan belajar siswa kelas X IPA 5 pada materi konsep mol dan perhitungan kimia di SMA Negeri 2 Surakarta Tahun Ajaran 2013/2014. Persentase keaktifan siswa siklus I dalam pembelajaran adalah 73,64 % meningkat menjadi 75,80 % pada siklus II, 2). penerapan Model Problem Based Learning (PBL) dengan penilaian portofolio dapat meningkatkan prestasi belajar siswa kelas X IPA 5 pada materi konsep mol dan perhitungan kimia di SMA Negeri 2 Surakarta Tahun Ajaran 2013/2014. Persentase ketuntasan prestasi belajar siswa siklus I adalah 88,12 %, pada siklus II persentase ketuntasan prestasi belajar siswa adalah 91,17 %. Persentase pencapaian aspek sikap siswa pada siklus I adalah 70,99 %, dan meningkat menjadi 75,69 % pada siklus II.
Kata Kunci: Konsep mol, Perhitungan kimia, Problem Based Learning (PBL), Keaktifan belajar, Prestasi belajar.  
ABSTRACT
This research’s aims to improve : 1). activeness of student learning X IPA 5 on the mole concept and chemical calculations at SMA N 2 Surakarta Academic Year 2013/2014, 2). student achievement X IPA 5 on the mole concept and chemical calculations at SMA N 2 Surakarta Academic Year 2013/2014.
This study was a Class Action Research (CAR), which consists of two cycles. Each cycle there are four stages of planning action, action, observation, reflection. Subjects were students of class X IPA 5 SMA Negeri 2 Surakarta Academic Year 2013/2014, amounting to 32 students. Source data comes from teachers and students. The research data were used in the form of student activity (visual activities, oral activities, listening activities, and writing activities) and achievement (cognitive aspects and aspects of attitude). The data collection was the method of test (written) and non-test (observation, interviews, document review, questionnaire). The data analysis technique was descriptive qualitative and quantitative research.
Based on the results of the research that has been done, it can be concluded as follows: 1). application of the model Problem Based Learning (PBL) with portfolio assessment can enhance the activity of students X IPA 5 on mole concept and chemical calculations in SMAN 2 Surakarta Academic Year 2013/2014. This can be seen by the results of the implementation of the action in the first cycle and the cycle I. In the first cycle, the percentage of active student in learning is 73.64 % and increased to 75.80 %, 2). application of the model Problem Based Learning (PBL) with portfolio assessment can improve student achievement X IPA 5 on concept mol and chemical calculation in SMAN 2 Surakarta Academic Year 2013/2014. This can be seen by the results of the implementation cycle I and cycle II. In the first cycle, the percentage of completeness student achievement is 88,12 %, in the second cycle completeness student achievement percentage is 91,17 %. In the aspect of physics students, the percentage of achievement in the first cycle is 70.99 %, and increased to 75.69 % in the second cycle.
Keywords: Mole concept, Chemical calculation, Problem Based Learning (PBL), Liveliness learning, Learning achievement