Acids and Bases Flashcards
what is the pH of an acid
⭐️PH:0-6.9
the pH of a base
⭐️ 7.1-14
characteristics of Acids
- taste sour
- conduct electricity
- found in foods
- corrosive
⭐️PH:0~6.9 - loses above properties when reacted with a base
characteristics of Bases
- tastes bitter
- conduct electricity
- feels slippery
- used in cleaning products
⭐️ PH: 7.1-14 - loses above properties when reacted with an acid
what pH is neutral
7
Indicators
Both acids and bases have one important common property: they each cause certain dyes to change colour.
These dyes are called indicators
Indicators and their colours in Acids and Bases
LITMUS: in Acids- red, in Bases- blue
BROMYTHOL BLUE: in Acids- yellow, in Bases- blue
PHENOLPHALEIN: in Acids- colourless, in Bases- dark pink/purple
does an ACIDIC solution have more hydrogen (H+) ions or hydroxide (OH-) ions
An ACIDIC solution contains more
hydrogen (H+) ions than hydroxide (OH-)ions.
does a BASIC solution have more hydrogen (H+) ions or hydroxide (OH-) ions
a BASIC solution contains more hydroxide (OH) ions than hydrogen (H+) ions.
does a NEUTRAL solution have more hydrogen (H+) ions or hydroxide (OH-) ions
A NEUTRAL solution contains EQUAL
concentrations of hydrogen ions and hydroxide ions.
Neutralization
The reaction of a base with an acid during which the properties of both the acid and the base dissappear
The products of this reaction are salt- ionic compound (metal and non metal)- and water
basically double replacement??
Models used to define Acids and Bases
- proposed by French chemist Antoine Laurent Lavoisier
- proposed, in 1883, by Swedish chemist Svante August Arrhenius
- The shortcomings from Arrhenius’s theory were recognized by Johannes Bronsted (1879-1947) and Thomas Lowry
Antoine Laurent Lavoisier Model
The first model was proposed by French chemist Antoine Laurent Lavoisier (1743- 1794) in 1770. He believed that acid properties were caused by the presence of oxygen
The name oxygen means
“producer of acids” butsubstances such as HIC and HBr were soon found to have acid properties even though they did not contain oxygen. A new model had to be proposed.
August Arrhenius Model
He defined an acid as a substance that donated a hydrogen ion to its water solution, while a base provides hydroxide (OH-) ions.
Bronsted-Lowry Model
An ACID is any substance that DONATES an H+ ion (which is actually a proton) in aqueous solution. Using this definition, an acid is therefore called a proton donor (AD bc Acids Donate)
A BASE is any species which ACCEPTS an H+ ion, or proton. Bases are therefore called
proton accepters (BA bc bases accept)
Notice that OH ions are not mentioned in this definition.
Amphiprotic
A substance like H2O which is capable of both donating and accepting protons is said to be AMPHIPROTIC
The acid and base that react in the reverse reaction are identified in the equation as…
a conjugate acid and a coningate base
A conjugate acid is…
the species produced when a BASE ACCEPTS a hydrogen ion/proton from an acid. (ex. HB)
A conjugate base is
A conjugate base is the species that results when an ACID DONATES a hydrogen ion/proton to a base. (ex. X)
Monoprotic
Acids and bases that can only donate or accept one proton are considered to be MONOPROTIC
Diprotic
Acids that contain two ionizable hydrogen atoms per molecule are called DIPROTIC
Triprotic
Acids with three hydrogen ions/protons to donate are called TRIPROTIC
Polyprotic
The term POLYPROTIC acid can be used for any has that can donate more than one hydrogen ion/proton.
All polyprotic acids will ionize in steps, losing _____ hydrogen ions at a time.
ONE
If a substance has more H+ ions than OH- ions…
Acid
If a substance has more OH- ions than H+ ions…
Base
For the Lewis Model what did Lewis propose? (3)
an acid is an ion or molecule with a vacant atomic orbital that can accept /share an electron pair.
a base is an ion or molecule with a lone electron pair that it can donate
According to the Lewis model, a Lewis acid is an electron-pair acceptor electron-pair donor
Summary of the 3 Models for Acids and Bases
Arrhenius: ACID- a substance that donates H+ to a water solution, BASE- a substance that donates an OH- to a water solution
Bronsted-Lowry: ACID- any substance that donates an H+ ion. BASE: any substance that accepts an H+ ion.
Lewis: ACID- accepts/shares an electron pair. BASE- donates an electron pair
what is a STRONG Acid
Acids that IONIZE COMPLETELY are called strong acids.
Because they produce the maximum number of ions, they are good conductors of electricity. The ionization of hydrochloric acid in water may be represented by the following equations, which have a single arrow pointing to the right:
Strength≠Concentration
acid ionization constant:
Ka. The value of Keq or the ionization of a weak acid
All bases that end in ____are strong bases
hydroxide (OH- )
Other strong bases include amides (-NH2) and oxides (-O) of
group I and group II metals, with the exception of beryllium.
if a weak base end in NHx, where will it accept the hydrogen?
any weak base that ends in NHx will accept the hydrogen on the END of its formula.
ex) C2H5NH2 (aq) + H2O (l) <—> C2H5NH3+ (aq) + OH-
if a weak base starts with H, where will it accept the hydrogen?
Any weak base that starts with a H (ex. HAs04) will accept the hydrogen at the BEGINNING of its formula.
ex) HAS04 (aq) + H20) <—> H2 As 04 (aq) + OH- (aq)
strong acids/bases
- completely ionize/split into + and -
- one way arrow —>
weak acids/bases
- only partially ionize
- double sided arrow <—>
writing ionization equation
add with water
ion product constant
Kw, is called the ion product constant for water: the value of Keq for the self-ionization of water
kw
= [H+] [OH-]
= 1.0 x10^-14
more [H+]…. Acid or Base
Acid
more [OH-]… Acid or Base
Base
equation for pH
pH= -log [H+]
equation for pOH
pOH= -log [OH-]
pOH of an acid
greater than 7.0
pOH of a base
less than 7.0
neutral pOH
7.0
pH + pOH = 14
for all strong monoprotic acids, the concentration of the acid IS the concentration of the H+ ion
ex) HCl (aq) —> H (aq) + Cl (aq)
0.10 M 0.10 M 0.10 M
equation for KaKb
KaKb= kw
kw= [H+] [OH-]
KaKb= Kw
Are Ka and Kb for strong or weak acids/bases
Weak
neutralization reaction
a reaction of an acid and a base in an aqueous solution to PRODUCE A SALT AND WATER
What is a salt/what is it made of
A salt is just an ionic compound made up of a cation (positive ion)- metal- from a base and an anion (negative ion)- non metal- from an acid.
Titration
a method for DETERMINING THE CONCENTRATION of a solution by reacting a known volume of the solution with a solution of known concentration.
3 Steps in Titration
1) A measured volume of an acidic or basic solution of unknown concentration is placed in a beaker then the pH of the solution is read and recorded.
2) A buret is filled with the titrating solution of known concentration. This solution is called the Standard solution, or titrant.
3) Measured volumes of the standard solution are slowly mixed in the beaker until the moles of the H+ from the acid equals the moles of the OH from the base. This is called the equivalence point
Equivalence point vs end point
Equivalence point: moles of the H+ from the acid equals the moles of the OH from the base. This is called the equivalence point
- when the graph is most steep (I think)
End point: The end
point of a titration is when the indicator turns the correct colour and you stop titrating.
The data from a titration may be used for 3 purposes:
1) To DETERMINE the CONCENTRATION of an acid using a base of KNOWN CONCENTRATION (or vice versa)
2) To PREDICT the VOLUME of added base (or acid) required to reach the equivalence point.
3) To DETERMINE the PURITY of an acid-containing, or base-containing sample.
Equation for Titration problems
MA VA= MB VB
MA = molarity of acid solution
VA = volume of acid solution’
MB = molarity of base solution
VB= volume of base solution
