A water supply company has been contaminated with a mixture of (Ba2+, Pb2+, Hg2+, Cr2+) from a nearby factory. One way to treat this problem is to precipitate out ALL the metals. They have called Environmental chemist Ms. Brothers to help solve this problem. a) Using your solubility table, help Ms. Brothers determine which anion should be used : carbonate or sulphate . Briefly explain why you choose that anion. b) Write the formula for the anion as a compound.
c) Write the net ionic equation for the formation of the solid compound containing Pb2+ and the anion you choose in (a)

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.