The temperature at which a given solid will melt is called melting point.
The melting range is the span of temperature from the point at which the crystals first begin to liquefy to the point at which the entire sample is liquid.
First we need to calculate the number of moles of FeS:
number of moles = mass (grams) / molecular mass (g/mol)
number of moles of FeS = 198.2/120 = 1.65 moles
From the chemical reaction we deduce that:
if 4 moles of FeS produces 8 moles of SO
then 1.65 moles of FeS produces X moles of SO
X = (1.65×8)/4 = 3.3 moles of SO
Now we can calculate the mass of SO:
mass (grams) = number of moles × molecular mass (grams/mole)
mass of SO = 3.3×64 = 211.2 g
First find the no. of moles of NaOH :
<span>30/1000 = 0.3 dm3 so no. of moles = 0.3*0.5 = 0.15 moles </span>
<span>as NaOH reacts with HNO3 in a ratio of one to one, there must have been 0.15 moles of HNO3 too </span>
<span>moles/volume = concentration </span>
<span>volume= 15/1000 = 0.15 dm3 </span>
<span>concentration = 1.15/0.15 = 1 mol.dm-3 </span>
<span>The quicker way would be to realize that you used twice as much NaOH so the HNO3 had to be twice as strong</span>