Choose all the true statements concerning the law of conservation of mass: a) when ice melts, mass is gained since water is more dense than ice. b)2h2+ o2 → 2h2o is a balanced equation c) a chemical change does not follow the law of conservation of mass d)a physical change does follow the law of conservation of mass e)a pencil breaking is an example of a physical change

How to convert a density of 0.791g/cm3 to lb/ft3

According to each substances heat of fusion, which of the items below requires more heat to be added per gram of substance to go from solid to liquid? silver sulfur water lead

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.