Concept explainers
A glass of water initially at pH 7.0 is exposed to dry air at sea level at
TABLE 21.1 Composition of Dry Air at Sea Level |
|
Gas |
Composition (% by Volume) |
|
78.03 |
|
20.99 |
|
0.94 |
|
0.033 |
|
0.0015 |
|
0.000524 |
|
0.00014 |
|
0.000006 |
Interpretation:
The pH of water at the equilibrium state is to be calculated.
Concept introduction:
Henry’s law is a gas law that states that the partial pressure of a gas and the concentration of a dissolved gas are directly proportional to each other.
Henry’s law is represented by the following expression:
Here,
is the mole fraction and
Equilibrium constant is expressed as follows:
Answer to Problem 68AP
Solution: pH is
Explanation of Solution
The partial pressure of carbon dioxide is calculated as follows:
Here,
is the mole fraction of
Substitute the value of
(from table
) and
Therefore, the partial pressure of carbon dioxide is
The concentration of
in water is calculated using Henry’s law as follows:
Here,
Substitute the values of
and
in the above equation:
Therefore, the concentration of
Let all of the dissolved
of carbonic acid is formed. Carbonic acid is a weak acid.
The equilibrium expression for carbonic acid in water is as follows:
The equilibrium constant is
).
The
Substitute the values of equilibrium concentration in the above equation:
This is a quadratic equation, by solving:
The pH of water at equilibrium is
Want to see more full solutions like this?
Chapter 21 Solutions
Chemistry
- The emission data in cps displayed in Table 1 is reported to two decimal places by the chemist. However, the instrument output is shown in Table 2. Table 2. Iron emission from ICP-AES Sample Blank Standard Emission, cps 579.503252562 9308340.13122 Unknown Sample 343.232365741 Did the chemist make the correct choice in how they choose to display the data up in Table 1? Choose the best explanation from the choices below. No. Since the instrument calculates 12 digits for all values, they should all be kept and not truncated. Doing so would eliminate significant information. No. Since the instrument calculates 5 decimal places for the standard, all of the values should be limited to the same number. The other decimal places are not significant for the blank and unknown sample. Yes. The way Saman made the standards was limited by the 250-mL volumetric flask. This glassware can report values to 2 decimal places, and this establishes our number of significant figures. Yes. Instrumental data…arrow_forwardSteps and explanation pleasearrow_forwardSteps and explanation to undertand concepts.arrow_forward
- Nonearrow_forward7. Draw a curved arrow mechanism for the following reaction. HO cat. HCI OH in dioxane with 4A molecular sievesarrow_forwardTry: Convert the given 3D perspective structure to Newman projection about C2 - C3 bond (C2 carbon in the front). Also, show Newman projection of other possible staggered conformers and circle the most stable conformation. Use the template shown. F H3C Br Harrow_forward
- Nonearrow_forward16. Consider the probability distribution p(x) = ax", 0 ≤ x ≤ 1 for a positive integer n. A. Derive an expression for the constant a, to normalize p(x). B. Compute the average (x) as a function of n. C. Compute σ2 = (x²) - (x)², the variance of x, as a function of n.arrow_forward451. Use the diffusion model from lecture that showed the likelihood of mixing occurring in a lattice model with eight lattice sites: Case Left Right A B C Permeable Barrier → and show that with 2V lattice sites on each side of the permeable barrier and a total of 2V white particles and 2V black particles, that perfect de-mixing (all one color on each side of the barrier) becomes increasingly unlikely as V increases.arrow_forward
- Chemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage LearningIntroductory Chemistry: A FoundationChemistryISBN:9781337399425Author:Steven S. Zumdahl, Donald J. DeCostePublisher:Cengage LearningGeneral Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage Learning
- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning