home / study / engineering / civil engineering / questions and answers / (1)list

Question

home / study / engineering / civil engineering / questions and answers / (1)list all the chemical equilibrium in a natural ... Question: (1)List all the chemical equilibrium in a natural ... Bookmark (1)List all the chemical equilibrium in a natural buffer system. (2)Find equilibrium concentration of Ca^2- in a water if the water is exposed to an atmosphere. The equilibrium aqueos CO_2 concentration is 1.19M the water pH is 8.1 and the water is in equilibrium with CaCO_3(s). Express the concentration of calcium in terms of M and mg/L as CaCO_3. Use the following reaction to solve problem (2). CO_2(aq) + H_2O<-> HCO_3- +H^+; K1=4.47*10^-7 HCO_3- <-> CO_3 2- + H^+; K2 = 4.68*10^-11 CaCO_3 <-> Ca^2+ + CO_3^2-; Ksp=4.57*10^-9

Explanation / Answer

PROBLEM -1.

A NAURALT BUFFER SOLUTION IS ONE WHOSE PH VALUE DOES NOT CHANGE UPON THE ADDITION OF A SMALL AMOUNT OF ACID OR BASE.

HERE ARE 2 TYPES OF NATURAL BUFFER SOLUTIONS

1.ACID BUFFER

2.BASIC BUFFER

1.ACID BUFFER MEANS A MIXTURE OF WEAK ACID AND ITS SALT WITH STRONG BASE

2.BASIC BUFFER MEANS A MIXTURE OF WEAK BASE AND ITS SALT WTIH STRONG ACID

THE PH OF AN ACID BUFFER IS

PH = PKa + LOG { (SALT) / ( ACID) ]

WHERE PKa IST HE DISSOCIATION CONSTANT OF WEAK ACID

SIMLARLY,

THE PH OF A BASIC BUFFER IS

PH = PKb + LOG { (SATL) / ( BASE) ]

WHERE PKb IS THE DISSOCIATION CONSTANT OF WEAK BASE.

PROBLEM-2.

THE GIVEN EQUATIONS ARE

CO2 + H2O = HCO3-1 + H+1   AND K1 = 4.47 * 10-7

HCO3-1 = CO3-2 + H+1 AND K2 = 4.68 * 10-11

CaCO3 = Ca+2 + CO3 -2   KSP = 4.57 * 10 -9

K1 = ( HCO3-1)*( H+1 ) /   (CO2) * (H2O)

OR

( HCO3-1) = K1* (CO2) * (H2O) / ( H+ )

AND

K2= ( H+1 ) *(CO3-2) / ( HCO3-1)

(CO3-2) = K2 * ( HCO3-1) / ( H+1 )

KSP = (Ca+2) * ( CO3-2) / Ca CO3 ( SOLID)

AND (H+ ) = ANI LOG OF (_8.1) = 7.9433 * 10-9

COMBINING THESE 3 EQUATIONS , WE GET

(Ca +2 ) = KSP .( H+ ) 3 / K1. K2 . (CO2) ( H2O)

= 4.57 * 10-9 * (7.9433* 10 -9)3 / 1.19 * 4.68 * 10-11 *4.47 * 10-7

   = 1.809 * 10-15

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.