Question

When hot lava reaches seawater, the salts in the water react with steam to form gaseous hydrochloric acid. You are given an unbalanced chemical equation for one such reaction and the volume of HCl(g) produced. Explain how you would find the mass of solid sea salt needed to produce the given gas volume.

Answer 1

Cl⁻ + H₂O(g) = HCl(g) + OH⁻

w - it is percent chloride ions in solid sea salt (as a rule 55%)

m - it is the mass of sea salt

m(Cl⁻)=mw/100

m(Cl⁻)/M(Cl)=V(HCl)/V₀

mw/{100M(Cl)}=V(HCl)/V₀

m=100M(Cl)V(HCl)/{wV₀}  (the mass of solid sea salt)

V₀=22.4 L/mol
M(Cl)=35.45 g/mol

for example:
V(HCl)= 1.0 L
w=55%

m=100×35.45×1.0/{55×22.4}=2.88 g

Answer 2

First, I would balance the chemical equation.

I would convert the volume of HCl to mol HCl by dividing by the molar volume.

Next, I would use the balanced equation to find out how many moles of the salt are needed to produce the moles of HCl.

Finally, I would multiply by the molar mass of the salt to convert moles to mass.