For the whole set of problems, always remember the Avogadro’s
number is 6.023*10^23 units per mole of a substance. Units could be atoms,
molecules or formula units.
The first question asks for the number of molecules of NaNO3.
The molar mass of NaNO3 is 85 grams per mole. So,
<span>150g NaNO3(1mole NaNO3/85 grams NaNO3)(6.023*10^23
molecules/1mole NaNO3)=1.063*10^24 molecules of NaNO3</span>
<span>5.7*10^46 molecules of NaNO3(1mole NaNO3/6.023*10^23
molecules)(85 grams NaNO3/1mole NaNO3) = 8.044*10^24 grams NaNO3</span>
For the molar mass of water, we have 18.02grams per mole.
301 moles H2O(18.02 grams H2O/1
mole H2O) = 5424.02 grams H2O
For the molar mass of sulfuric
acid, we have 98.08 grams per mole.
25g H2SO4(I mole H2SO4/98.08g H2SO4) =
0.2549 mole H2SO4
For the molar mass of Ca(OH)2,
we have 74.1 grams per mole.
252gCa(OH)2(1mol/74.1g)(6.023*10^23/1mol)
= 2.048*10^24 molecules of Ca(OH)2
For the molar mass of calcium,
we have 40 grams of Ca per mole.
6.7*10^35 atoms Ca(1 mole
Ca/6.023*10^23 atoms)(40g Ca/1mol Ca) = <span>4.45*10^13 grams Ca</span>
