In the above equation how many moles of water can be made when 180.7 grams of HNO3 are consumed?

Question

S   +   6 HNO₃  -->  H₂SO₄  +  6 NO₂  +   2 H₂O

In the above equation how many moles of water can be made when 180.7 grams of HNO₃ are consumed?

Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0

Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:

Element	Molar Mass
Hydrogen	1
Nitrogen	14
Sulfur	32
Oxygen	16

Answer 1

We will assume that enough sulfur is provided to completely consume the entire 180.7 g of HNO₃. We can use stoichiometry to link the number of moles of products generated from the reactants. First, calculate the number of moles of HNO₃ that are provided using the mass of this reactant and the molar masses provided.

M_HNO3 = Molar mass of HNO₃:

H: 1 g/mole

N: 14 g/mole

O₃: 16*3 = 48 g/mole

HNO₃: 1+14+48 = 63 g/mole

n_{HNO3, consumed} = Moles of HNO3 provided (and subsequently consumed):

n_{HNO3, consumed} = m_{HNO3, consumed} / M_HNO3

= 180.7 g / 63 g/mole

= 2.8682 moles

Now we can relate the number of moles of HNO₃ consumed to the number of moles of H₂O (water) made using the coefficients in the chemical reaction provided. Two moles of water are made for every six moles of HNO₃ consumed, so:

n_{H2O, generated} = n_{HNO3, consumed} * (2 H₂O / 6 HNO₃)

= 2.8682 mol * 2/6

= 0.956 mol = 1.0 mol

If it asked for mass of water, calculate the molar mass of water and convert:

M_H2O = 2*1 + 1*16 = 18 g/mol

m_{H2O, generated} = 0.956 mol * 18 g/mol

= 17.2 g