<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles. We calculate as follows:
</span>1.40x10^23 molecules of N2 ( 1 mol / 6.022 x 10^23 molecules ) ( 28.02 g / mol ) = 6.51 g N2
<span>The density of an iceberg is less than that of water and that is why it floats. It is the same as ice cubes floating on water too. Water is a very unique substance in that it is one of few compounds where cooling it past freezing point decreases its density (study hydrogen bonds). The possible answers are therefore A or C. If the majority of the ice is below the water then it should be clear from common sense that A is the correct answer as it would mostly float on the top with just a little under the surface if the answer were as low as C. See Archimedes Principle for an explanation of how much of the ice floats and how much is underwater.</span>
Convert 57.6 L to dm3 and divide it by 24
The given salts are Barium chloride, lead chloride and zinc chloride.
The balanced chemical reaction between barium chloride and sodium sulfate:

The balanced chemical reaction between lead chloride and sodium sulfate:

The balanced chemical reaction between zinc chloride and sodium sulfate:

Both Barium chloride and lead chloride produce a white precipitate of their respective sulfates upon reaction with sodium sulfate. But BaCl2 is readily soluble in water where as Lead chloride is insoluble in water.
Therefore, the compound is barium chloride.
The testing of the acidities of the compounds to determine the combination that will keep the drug intact before it reaches the intestines is a part of EXPERIMENTATION process. The experimentation is done in order to prove or answer different queries that were raised during the hypothesis making.