You have been given a mixture of water and a unknown solid substance. your teacher asks you to perform a heating process to determine what the unknown substance is. when the temperature reaches 100 °c, the water begins to boil and you are left with a white crystalline substance. when your thermometer reaches 200 °c, everything in the container becomes a liquid. what is the unknown substance? a) lead b) aluminum c) table salt d) table sugar

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

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ

How is an endothermic reaction identified