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守恒法是中学化学计算中一种常用的、重要的方法和技巧,根据题意找出一种或几种一变量建立关系式,从而简化解题过程,达到快速解题的目的。1.质量守恒法:质量守恒主要包括两项内容:(1)化学反应前后总质量不变,(2)化学反应前后某原子或原子团的质量不变。例1:将20gM物质,5 gN物质,9 gP物质混合加热发生化学反应,经充分反应后的混合物中含5gM物质,20gP物质,还含有一种新物质Q,若M、N、P、Q的相对分子质量分别为30、20、44、18,
Conservation Law is a commonly used and important method and skill in middle school chemistry calculation. According to the problem, one or several kinds of variables are established to establish the relation so as to simplify the process of solving problems and achieve the purpose of solving problems quickly. 1. The law of conservation of mass: Conservation of mass mainly includes two parts: (1) the total mass before and after the chemical reaction is constant, and (2) the mass of an atomic or atomic mass does not change before and after the chemical reaction. Example 1: 20gM substance, 5gN substance, 9gP substance were mixed and heated for chemical reaction. The fully reacted mixture contained 5gM substance, 20g substance P, and a new substance Q. If M, N, P, Q The relative molecular mass of 30,20,44,18,