CH 7 chem
pH means
"power" of hydrogen. pH = -log[H+]
Which of the following aqueous solutions has the highest concentration of H+ ions? 0.10 MHNO3 0.10 MNH3 0.10 MCH3COOH
0.10 MHNO3
pH of solution with hydroxide ion concentration of 1 x 10^-5 M
9
Arrhenius Theory Base:
A substance that produces hydroxide ions (OH-) in aqueous solution.
Brønsted-Lowry definition of an acid
Anything that donates a proton
According to the Arrhenius theory, an acid is any substance that dissolves in water to produce _____. H+ OH- salts ions a bitter taste
H+
Equation showing how ammonia (NH3) acts as a Bronstede-Lowry base in water
NH3 + H2O ---> NH4 + OH
T/F A conjugate acid-base pair form a buffer solution.
True
T/F NH3 is a weak base
True
Acetic acid forms in ______stored wines.
improperly
A common name for hydrochloric acid is
muriatic acid.
Sulfuric acid is the leading chemical substance produced in
the United States
pH is a means of expressing
the acidity or basicity of a solution.
Water molecules are the result of the reaction between
*hydrogen ions and hydroxide ions. H+ + OH- ↔ H2O In water this reaction is DYNAMIC and goes back and forth (REVERSIBLE) but when on average the concentrations do not change, the reaction is said to be in EQUILIBRIUM.
Ammonia (NH3) problems
-Ammonia turns litmus blue but does not contain the OH- ion. -Ammonia can be used to neutralize HCl solutions.
Brønsted-Lowry definition of base
-Anything that accepts a proton -A base is any substance that removes H3O+ ions from solution.
Limitations of the Arrhenius Theory:
-H+ ions do not exist in water solution. Protons react with water to form hydronium ions (H3O+). H+ + H2O → H3O+ -does not explain the basicity of ammonia and similar compounds. -applies only to reactions in aqueous solution.
The H3O+ ion is the hydronium ion;
-In water, H+ ions always associate with H2O molecules. -Chemists often use H+(aq) and H3O+(aq) interchangeably to refer to a hydronium ion.
Base uses
-Sodium hydroxide and potassium hydroxide are found in most chemistry laboratories. -used in processing petroleum and cotton, and in soap and plastic manufacturing. -Sodium hydroxide is the active ingredient in products such as Drano -Sodium bicarbonate can be found in most homes as baking soda and is an active ingredient in many antacids. -When taken as an antacid, sodium bicarbonate neutralizes stomach acid, relieving heartburn and sour stomach.
Bases: Properties
-have a bitter taste. -have a slippery feel. -turn red litmus paper blue.
Acids have the following properties:
-have a sour taste. -dissolve many metals. -turn blue litmus paper red.
Autodissociation is
-opposite of neutralization The dissociation of water to form H3O+ and OH- Creates an equal number of each ion
Which of the following aqueous solutions has the lowest concentration of H+ ions?0.10 MHNO3 0.10 MNH3 0.10 MCH3COOH
0.10 MNH3
Write equations showing 1)the ionization of sulfuric acid (H2SO4) in water 2) the ionization of solid potassium hydroxide (KOH) in water.
1)H2SO4(aq) → 2 H+(aq) + SO42-(aq) 2)KOH(s) → K+(aq) + OH-(aq)
The pH of milk of magnesia is between which two whole numbers?Milk of magnesia has a hydrogen ion concentration between 1.0×10−10M and 1.0×10−11M.
10 and 11
pH that has hydrogen ion of 1 x 10^-11
11
If the concentration of a dilute solution of nitric acid is 0.01 M, what is the pH of that solution?
2
Neutralization
Acid + Base → Water + Salt
Arrhenius Theory of Acid:
Acid: A molecular substance that ionizes in aqueous solution to form hydrogen ions (H+). NOTICE: The ionizing hydrogen usually connected to an electronegative atom—very common oxygen.
Brønsted-Lowry Theory:
Acid: Proton donor. HCI + H2O → H3O+ + CI- Base: Proton acceptor. NH3 + H2O → NH4+ + OH- Acid give proton to base
Which of the following is a correct definition of an acid that is not dependent upon the solvent?Acids are proton donors. Acids produce hydroxide ions. Acids are proton acceptors. Acids produce hydronium ions.
Acids are proton donors.
Aluminum hydroxide is a popular antacid. The formula of aluminum hydroxide is
Al(OH)3.
Write an equation showing the reaction with water of HNO3 as a Brønsted-Lowry acid. What is the role of water in the reaction?
As a Brønsted-Lowry acid, HNO3 donates a proton to a water molecule, forming a hydronium ion and a nitrate ion. HNO3(aq) + H2O → H3O+(aq) + NO3-(aq) Water is a Brønsted-Lowry base in this reaction; it accepts the proton from the HNO3.
Which of the following is the correct balanced equation for the neutralization of barium hydroxide with hydrochloric acid?BaOH2 + 2 HCl → BaCl2 + H2O BaOH + HCl → BaCl + H2O Ba(OH)2 + HCl → BaCl2 + H2O Ba(OH)2 + 2 HCl → BaCl2 + 2 H2O
Ba(OH)2 + 2 HCl → BaCl2 + 2 H2O
Give the formula for the base formed by the addition of water to barium oxide (BaO).
BaO + H2O → Ba(OH)2
Better buffer ; solution of ammonia with ammonium acetate or solution of sodium hydroxide with sodium acetate ? Why?
Buffer solutin is made from a mixture of weak acid and salt or weak base and its salt. Ammonia is a weak base while Sodium hydroxide is a strong base. Therefore, the combo of ammonia and ammonium acetate would meet requirement of weak base + salt and other would not.
Which of the following pairs could form a buffer? HCl and NaCl HCl and NaOH C6H5COOH and C6H5COONa
C6H5COOH and C6H5COONa
CH3CH2COOH+H2O→CH3CH2COO−+H3O+ In the given reaction in aqueous solution, identify which of the reactants is the; acid base conjugate base of the acid conjugate acid of the base
CH3CH2COOH H2O CH3CH2COO H3O
Acetic Acid reacts with water to form
CH3COO +H3O
Which of the following is a common ingredient in antacids? HCl KOH CaCO3 Ca(OH)2
CaCO3
The cheapest and most widely used commercial base is ________
CaO (lime)
Write the product for the result of dichlorine oxide (Cl2O) reacting with water (the product will have only 1 equivalent (atom) of chlorine in it).
Cl2O+ H2O → 2HOCl
__________arrow shows reaction not highly favored, in equilibrium.
Double-headed HCN(aq) ↔ H+(aq) + CN-(aq) NH3(aq) + H2O ↔ NH4+(aq) + OH-(aq)
double-headed arrow (H+ + OH- ↔ H2O) and single-headed arrow over oppositely pointed single-headed arrow of different lengths were used for __________. The latter has advantage in depicting which side of reaction is favored (longer arrow). Pure water autodissociation produces only 10-7 M H+.
EQUILIBRIUM
What type(s) of ion(s) is/are present in every aqueous solution?
H+ and OH−
Sulfuric acid is the leading chemical produced and used industrially. What is the formula for sulfuric acid?
H2SO4
What is the product when SeO2 + H2O → ? Se(OH)2 SeH2O2 Se + H2O3 H2SeO3 H2SeO2 + O
H2SeO3 Nonmetal oxides are acidic anhydrides. They form their corresponding acid when they interact with water.
A buffer solution is made from HCOOH and HCOONa . Added acid will react with
HCOO
When an acid name ends in -ic acid, there is often a related acid whose name ends in -ous acid. The formula of the -ous acid has one less oxygen atom than that of the -ic acid.With this information, write formulas for nitrous acid.
HNO2
Write the product for the reaction of potassium oxide (K2O) with water.
K2O + H2O → 2KOH
When added to water, which of the following would produce a base? Li2O CO2 SO3 F2
Li2O
Which of the following ingredients would NOT be an active ingredient in an antacid? NaBr CaCO3 Mg(OH)2 NaHCO3
NaBr
8 x 10^-4 M . pH?
PH of 1 x 10^-4 = 4 10 x 10^-4 = 10^-3 = pH 3 So between 3 and 4
Salts are formed from neutralization, are ionic compounds, and can be simple or ______
Polyatomic
Which of the following is an example of a nonmetal oxide?SO2 Na2O LiOH H2SO4
SO2
Give the formula for the acid formed when sulfur dioxide reacts with water.
SO2 + H2O → H2SO3
formula for sulfur dioxide reacting with water
SO2 + H2O----> H2SO3
When added to water, which of the following would produce an acid? NH3 Na SO3 BaO
SO3
What is the conjugate base of HSO3-?
SO32-
Anhydride of selenic acid
SeO3
__________arrow shows reaction very highly favored.
Single-headed HCl(aq) → H+(aq) + Cl-(aq) NaOH(aq) → Na+(aq) + OH-(aq)
How do strong and weak bases differ
Strong bases ionize completely in water , weak bases react too but only 5% or less or weak base undergo the reaction
T/F If a compound is a base according to the Arrhenius definition, it will also be a base according to the Bronsted-Lowry definition.
True
Acids Taste Sour bc
When you first put sour food in your mouth H+ ions react with protein molecules on your tongue, protein molecules change shape, sending an electrical signal (a nerve impulse) to your brain that you experience as a sour taste.
Hydrocyanic is classified as a weak acid in water. This means that it produces
a relatively small fraction of the maximum number of possible hydronium ions.
According to Arrhenius, an acid and a base will react to give
a salt plus water.
Rain with a pH of less than 5.6 is considered to be
acid rain.
An unknown substance is added to a solution and the pH decreases. The substance is best described as a(n)
acid.
Coffee is _______overall, but bases present in coffee—such as caffeine—impart a bitter flavor.
acidic
When nonmetal oxides react with water, the resulting solution is ________.basic acidic neutral salty
acidic
Nonmetal oxides present in air react with water, forming
acidic solutions.
Excessive use of antacids can lead to an increase in the pH of blood, a condition known as
alkalosis
Acid rain is caused by acidic pollutants in the air. Which of the following pollutants does NOT contribute to acid rain?
ammonia, NH3
Acetic acid is an example of a carboxylic acid, which is
an acid containing the COOH grouping of atoms, known as the carboxylic acid group
A compound that changes color when it is placed into an acidic or a basic solution is
an acid-base indicator.
Nonmetal oxides
are acidic anhydrides. SO3 + H2O → H2SO4
The compound CH3NH2 reacts with water to form CH3NH3+ and OH-. In this reaction, CH3NH2 is acting as a(n) acid. catalyst. salt. base.
base.
Many metal oxides, such as Na2O, dissolve in water to produce _____. acids bases neutral salts covalent compounds a sour taste
bases
Soap itself is ______, and its slippery feel is characteristic of bases.
basic
Some household cleaning solutions, such as ammonia, are also ________and have the typical slippery feel.
basic
Metal oxides
basic anhydrides. Lime (calcium oxide) reacts with water to form slaked lime (calcium hydroxide). CaO + H2O → Ca(OH)2
Bases are less common in foods than acids because of their ________taste
bitter
What is the hydrogen ion concentration of a solution that has a pH of 5?
c(H+) = 1×10−5
Lime can be slaked by reacting with water to make
calcium hydroxide [Ca(OH)2].
The amount of acid (or base) in a solution is determined by
careful neutralization.
Phenolphthalein has often been used to monitor the progress of an acid-base neutralization reaction. What color will phenolphthalein be when there is an excess of acid present?
colorless
Strong bases ionize / Weak bases ionize
completely in water solution. NaOH(aq) → Na+(aq) + OH-(aq) only partially in water solution. NH3(aq) + H2O ↔ NH4+(aq) + OH-(aq)
Strong acids ionize,Weak acids ionize
completely in water solution. HCl(aq) → H+(aq) + Cl-(aq) only partially in water solution. HCN(aq) ↔ H+(aq) + CN-(aq)
Conjugate acid-base pairs are
compounds or ions that differ by one proton (H+). For example, the chloride ion (Cl-) is the conjugate base of hydrochloric acid (HCl).
Autodissociation
dissociation of water to form H3O and OH
Which property is best attributed to acids?feel slippery on the skin dissolve active metals such as zinc and iron, producing hydrogen gas bitter taste cause litmus indicator dye to turn blue
dissolve active metals such as zinc and iron, producing hydrogen gas
A salt that can conduct electricity when it is dissolved in water is a(n)
elecrolyte.
Kw is the
equilibrium constant
Ammonia is produced for use as
fertilizer and in household cleaning products. Annual U.S. production is about 11 billion kg.
Sulfuric acid used to manufacture
fertilizers and industrial chemicals, and it is the acid of automotive batteries. Production is 40 billion kg per year.
Strong Acids usually in _____
group 7
Acid reducers
have been displacing antacids as a way to combat hyperacidity.
Concentrated acids and bases are corrosive to tissue and are __________.They can__________ proteins in living cells.
health hazards,denature
The H+ ions are ______ reactive. In aqueous solution, they bond to water molecules according to the reaction
highly
NaOH, also known as lye, can be purchased for
home use as oven cleaner or drain cleaner. It is used commercially to make soap. Annual U.S. production is 9 billion kg.
Reaction of HBr and water gives you
hydronium ion and Br
H3O+ is the
hydronium ion.
Salts are
ionic compounds composed of cations other than hydrogen and anions other than hydroxide.
Higher # in the exponent, the ___________ acidic it it
less ex 10 ^-10 less acidic then 10 ^-5
Lime (CaO) is produced by heating
limestone (CaCO3). CaCO3 + heat → CaO + CO2
Slaked lime is used to make
mortar and cement and to sweeten soil. Annual U.S. production is 22 billion kg.
The reaction of an acid with a base is called
neutralization
According to the Arrhenius Theory, is every compound that contains OH a base?
no, to be an Arrhenius base the OH group must be paired with a metal .
(CO2),(SO2), (NO), and (NO2) are the major _______ ________responsible for acid rain formation.
nonmetallic oxides
less polar covalent C-H is usually____ ________
not ionizable
Hyperacidity
occurs when the stomach secretes too much acid. Antacids are often taken to neutralize excess acid and reduce the symptoms of hyperacidity.
Our aversion to the taste of bases is probably an adaptation to protect us against alkaloids which are
organic bases found in plants that are poisonous
What is the pH of a solution that has a hydrogen ion concentration of 1.0×10−8 M ?
pH = 8.0
A buffer
resists changes in pH when small amounts of a strong acid or a strong base are added. is made up of a weak base and its conjugate acid. is made up of a weak acid and its conjugate base.
Soil can be "sweetened" by adding
slaked lime [Ca(OH)2].
Acids tend to taste _____, while bases tend to taste _____. sour/bitter sour/sweet sweet/bitter bitter/sour bitter/sweet
sour/bitter
Classify HI as a strong acid, a weak acid, a weak base, or a strong base.
strong acid
Acids
substances that produce H+ ions in solution. H+ ions often called "protons" produces H+ ions in aqueous solution.
The acid in automobile batteries is
sulfuric acid.
Bases feel slippery because
they react with oils on your skin to form soaplike substances.
The human body has wonderful mechanisms for maintaining the proper pH of
tissue, blood, and body fluids.
Buffer solutions contain
weak acid & its conjugate base. capable of maintaining a nearly constant pH when small amounts of acid or base are added.
Buffer formulation
weak acid + conj base or weak base + conj acid
A solution with a pH of 8 will be
weakly basic.
