Is the law of conservation of matter followed in the reaction below?

According to the vsepr theory what is the shape of a molecule that has a central atom valence three other items with no lone pairs of electrons

Fred is studying a substance that is made out of only one element. this means that

You are attempting to recrystallize a crude product mixture. you add the appropriate amount of hot solvent and are allowing the solution to slowly cool to room temperature. however, at room temperature no crystals have appeared, which of the following methods should be used to induce crystallization? choose all correct answers. a) place the flask in an ice bath. b) swirl the contents of the flask. c) add a small seed crystal of the desired product. d) scratch the inside of the glassware using a stir rod. it can be multiple choices