The acidity of a solution is typically assessed experimentally by measurement of its pH. The pOH of a solution is not usually measured, as it is easily calculated from an experimentally determined pH value. The pH of a solution can be directly measured using a pH meter (
[link] ).
(a) A research-grade pH meter used in a laboratory can have a resolution of 0.001 pH units, an accuracy of ± 0.002 pH units, and may cost in excess of $1000. (b) A portable pH meter has lower resolution (0.01 pH units), lower accuracy (± 0.2 pH units), and a far lower price tag. (credit b: modification of work by Jacopo Werther)
The pH of a solution may also be visually estimated using colored indicators (
[link] ).
(a) A universal indicator assumes a different color in solutions of different pH values. Thus, it can be added to a solution to determine the pH of the solution. The eight vials each contain a universal indicator and 0.1-
M solutions of progressively weaker acids: HCl (pH = l), CH
3 CO
2 H (pH = 3), and NH
4 Cl (pH = 5), deionized water, a neutral substance (pH = 7); and 0.1-
M solutions of the progressively stronger bases: KCl (pH = 7), aniline, C
6 H
5 NH
2 (pH = 9), NH
3 (pH = 11), and NaOH (pH = 13). (b) pH paper contains a mixture of indicators that give different colors in solutions of differing pH values. (credit: modification of work by Sahar Atwa)
Key concepts and summary
The concentration of hydronium ion in a solution of an acid in water is greater than 1.0
10
−7M at 25 °C. The concentration of hydroxide ion in a solution of a base in water is greater than 1.0
10
−7M at 25 °C. The concentration of
in a solution can be expressed as the pH of the solution; pH = −log
The concentration of OH
− can be expressed as the pOH of the solution: pOH = −log[OH
− ]. In pure water, pH = 7.00 and pOH = 7.00
Key equations
pOH = −log[OH
− ]
[H
3 O
+ ] = 10
−pH
[OH
− ] = 10
−pOH
pH + pOH = p
Kw = 14.00 at 25 °C
Chemistry end of chapter exercises
Explain why a sample of pure water at 40 °C is neutral even though [H
3 O
+ ] = 1.7
10
−7M .
Kw is 2.9
10
−14 at 40 °C.
In a neutral solution [H
3 O
+ ] = [OH
− ]. At 40 °C,
[H
3 O
+ ] = [OH
− ] = (2.910
−14 )
1/2 = 1.7
10
−7 .
The hydronium ion concentration in a sample of rainwater is found to be 1.7
10
−6M at 25 °C. What is the concentration of hydroxide ions in the rainwater?
what's the difference between a firm and an industry
Abdul
firm is the unit which transform inputs to output where as industry contain combination of firms with similar production 😅😅
Abdulraufu
Suppose the demand function that a firm faces shifted from
Qd 120 3P
to
Qd 90 3P
and the supply function has shifted from
QS
20 2P
to
QS
10 2P .
a) Find the effect of this change on price and quantity.
b) Which of the changes in demand and supply is higher?
Demand curve shows that how supply and others conditions affect on demand of a particular thing and what percent demand increase whith increase of supply of goods
Israr
Hi Sir please how do u calculate Cross elastic demand and income elastic demand?
Abari
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