Question

According to the following reaction, how many moles of water are necessary to form 0.329 moles phosphoric acid?

diphosphorus pentoxide (s) + water (l) phosphoric acid (aq)

moles water

According to the following reaction, how many moles of iron(III) chloride will be formed upon the complete reaction of 0.555 moles iron with excess chlorine gas?

iron (s) + chlorine (g) iron(III) chloride (s)

moles iron(III) chloride

Answer 1

1)

P₂O₅   +   3 H₂O ---------------> 2 H₃PO₄

from the balanced equation :

3 mol H2O   --------------> 2mol H3PO4

   ??            -------------> 0.329 mol H3PO4

moles of H2O = 0.329 x 3 / 2 = 0.494

moles of water needed = 0.494 mol

2)

2 Fe (s)   + 3 Cl2 (g)    -----------> 2 FeCl3 (s)

2 mol Fe (s) -------------> 2 mol FeCl3

0.555 mol Fe   -----------> ??

moles of iron (III) chloride = 0.555 mol