Question

A student noted down the following precautions for the experiment "to verify the law of conservation of mass in a chemival reaction" (a)the spring balance should be held vertical while in use (b) before making use of the spring balance it must be insured that its pointer is at zero mark (c)the reading of the balance should be noted only when its pointer comes to rest (d)mixing of 2 solutions should be done quickly (e)chemical reaction shoiuld be exothermic

Answer 1

(d) mixing of two solutions should be done quickly and (e) chemical reaction should be exothermic                                                

Answer 2

d) mixing of two solutions should be done quickly. e) chemical reaction should be exothermic.