1- Law of Conservation of Mass 2- Law of Constant Proportions/ Composition 3- Law of Multiple Proportions. Need help in Chemistry? Are you in 11th or 12th grade? Then you shall find these videos useful. Barring 10 videos on "IUPAC Nomenclature" and 8 videos on "Comparing acid base strengths of organic acids", which I made as they were requested by students. I have uploaded videos following the chapters of the NCERT Text book for Class 11 to be followed by class 12. I am making the videos in sequence so You can play the videos from the beginning to do the entire course. I hope you work with your teachers and me and 'kill it' in the final exams - Boards in India or Regents in the USA.. Wishing you all the best!! HAPPY STUDYING!! If you have questions regarding the video, please do write in the comments. I will get back to you as soon as possible.