The law of reciprocal proportions, also known as the law of multiple proportions or Dalton's law, refers to a fundamental chemical principle that states that the ratio of the masses of two elements combining with a fixed mass of another element is always in small whole numbers. This law is essential in chemical calculations and plays a significant role in determining the ratios of reactants and products in chemical reactions. Some synonyms for the law of reciprocal proportions include the law of definite proportions, the law of mass conservation, and the law of stoichiometry. These terms are often used interchangeably in scientific literature and highlight the importance of understanding the fundamental principles of chemistry.