Question

.Sea water contains an average of 1.08 3 103 ppm of Na1 and 270 ppm of SO4 22. Calculate
(a) the molar concentrations of Na1 and SO4 22 given that the average density of sea water is 1.02 g/mL.

(b) the pNa and pSO4 for sea water.

Answer 1

Answer:

Explanation:

Ans.for calculation of molar concentration of Na+

Na+ = 1.08 * 10^3 ppm = 1080 mg/L = 1080 * 10^-3g/23g/mol = 0.046M

SO42- = 270 * 10^-3/96 = 2.81 * 10^-3 M

pNa = -log Na+ = -log(0.046) = 1.337

pSo42- = -log(SO42-) = -log(2.81 *10^-3) = 2.55

Answer 2

The sea water contains an average the molar concentrations the average density of sea water the $4.79*10^{-2}mol/L$.

Average the molar concentrations the average density of sea water :

ppm of $N_{a}^{+}=1.08*10^{3}$

The density of sea water $=1.02g/mL$

molar concentration of $N_{a}^{+}=1.08*10^{3}ppm$

$=1080mg/L$

$=1080*10^{-3}g/23g/mol$

$=0.046M$

$SO_{4}^{2-}=270*10^{-3}/96$

$=2.81*10^{-3}$

$=4.79*10^{-2}mol/L$.