Paper Title
Development of Experiment Student Worksheet based Guided Inquiry on Acid and Base Topic

Chemistry learning process is often only aimed at the achievement of students' cognitive, whereas the purpose of education is not only cognitive, but also includes affective and psychomotor. Chemistry is an experimental science. The learning process in the Laboratory (experiment) can help students to learn in understanding the chemical concepts. Prove various concepts and doing simple research. Acid-Base is one of the topics of chemistry that require practicum in the learning process. The Types of student worksheet available has not yet guide students to find concepts. This research aims to generate Experiment Student Worksheets guided inquiry on the topic of acid-base valid and practical. This development research using stages of 4-D model . Data collection instruments used in this research is the validation sheet and questionnaire. experiment Work sheet developed validated by five people validator and Practicality test done in class XI IPA Senior High School 9 of Padang. the data obtained were analyzed using Cohen Kappa Formula. Based on the validity of the test results obtained by the average value of moment kappa of 0.77 with the category of high validity and Practicality test of the students obtained average value 0.88 with the category of very high practicality. while at the teacher practicality obtainable momen kappa 0.8845 with very high practicality categories. Based of this research concluded that the experiment work sheet of acid-base guided inquiry valid and very practically, so it can be used in learning activities. Keywords - Experiment worksheet, Guided Inquiry, acid - base, 4-D Models.