ACID-BASE
What are some of the physical and chemical characteristics of an base?
1. Bitter taste. 2. They don't react with metals. 3. They turn red Litmus paper blue. 4. They have a pH above 7 (if dissolved in water). 5. Feels slippery. 6. A solution with a dissolved base will conduct electricity (as do acids and salts).
What are some of the physical and chemical characteristics of an acid?
1. Sour or tart taste. 2. Reacts with metals that are more active (activity series) than the hydrogen in an acid (producing hydrogen bubbles). 3. Turns blue Litmus paper red 4. Has a pH below 7. Allows a solution to conduct electricity (dissolved salts and bases do this as well). 6. Corrosive to metals that are more active (activity series) than the hydrogen in an acid.
What does the term "neutral pH" mean to a chemist?
A "neutral pH" mean a solution is at or near a pH of 7.
What is a diprotic acid?
A diprotic acid has two ionizable hydrogen atoms (this can also be stated as having two ionizable protons). For example, sulfuric acid (H₂SO₄) has 1 ionizable hydrogen atom (or proton). Arrhenius Theory: H₂SO₄(aq) → H⁺(aq) + HSO₄⁻(aq) HSO₄⁻(aq) → H⁺(aq) + SO₄²⁻(aq) Bronsted-Lowry Theory: H₂SO₄(aq) + H₂O → H₃O⁺(aq) + HSO₄⁻(aq) HSO₄⁻(aq) + H₂O → H₃O⁺(aq) + SO₄²⁻(aq)
What is a hydrogen ion?
A hydrogen ion is a hydrogen atom that has lost its electron. The formula is H⁺. Since a typical hydrogen atom is made of only one proton and one electron, and since a hydrogen ion is a hydrogen atom that has lost its electron, a hydrogen ion is, therefore, also a proton.
What is a hydronium ion?
A hydronium ion is a water molecule that is covalently bonded to a hydrogen ion (a hydrogen ion is a proton).
What is a hydroxide ion?
A hydroxide ion is made of one oxygen atom and one hydrogen atom but with one more electron than protons giving it a negative charge.
What is a monoprotic acid?
A monoprotic acid has one ionizable hydrogen atom (this can also be stated as having one ionizable proton). For example, hydroiodic acid (HI) has 1 ionizable hydrogen atom (or proton). Arrhenius Theory: HI(aq) → H⁺(aq) + I⁻(aq) Bronsted-Lowry Theory: HI(aq) + H₂O → H₃O⁺(aq) + I⁻(aq)
What is a polyprotic acid?
A polyprotic acid more than one ionizable hydrogen atom (this can also be stated as having more than one ionizable proton).
What is another term for the hydrogen ion in acid-base chemistry?
A proton.
What is a chemist's definition of a salt?
A salt is the product of an Arrhenius acid-base reaction other than the water. Example: H₂SO₄(aq) + KOH(sq) → KHSO₄(aq) + H₂O(𝓵) H₂SO₄ is an Arrhenius acid (sulfuric acid). KOH is an Arrhenius base (potassium hydroxide). KHSO₄ is a salt (potassium hydrogen sulfate also called potassium bisulfate). The symbolic equation for all Arrhenius acid-base reactions is: HA + BOH → HOH + BA. In this symbolic equation, HA is any Arrhenius acid, BOH is any Arrhenius base, HOH is water (just like H₂O), and BA is any salt.
What is a triprotic acid?
A triprotic acid has three ionizable hydrogen atoms (this can also be stated as having three ionizable protons). For example, phosphoric acid (H₃PO₄() has three ionizable hydrogen atoms (or protons). Phosphoric acid has 3 ionizable hydrogens, there are 3 dissociation equations: Arrhenius Theory: H₃PO₄(aq) → H⁺(aq) + H₂PO₄⁻(aq) H₂PO₄⁻(aq) → H⁺(aq) + HPO₄²⁻(aq) HPO₄²⁻(aq) → H⁺(aq) + PO₄³⁻(aq) Bronsted-Lowry Theory: H₃PO₄(aq) + H₂O → H₃O⁺(aq) + H₂PO₄⁻(aq) H₂PO₄⁻(aq) + H₂O → H₃O⁺(aq) + HPO₄²⁻(aq) HPO₄²⁻(aq) + H₂O → H₃O⁺(aq) + PO₄³⁻(aq)
What is the one weak base that you need to know by it's common name?
Ammonia - NH₃
What pH will an acidic solution have?
An acidic solution will have a pH of less than 7.
What pH will a basic solution have?
An basic solution will have a pH of greater than 7.
In titration chemistry, what is an indicator?
An indicator (or pH indicator) is a chemical that changes color at the pH needed to show that and endpoint has been reached. In titration involving chemicals that are not acids or bases, an indicator can change color when a certain concentration of product has been produced.
What are the weak acids?
Any acid that is not one of the strong acids, you can consider it to be a weak acid.
What does pOH mean?
Arrhenius Theory and Brønsted-Lowry Theories: The small letter p in pOH stands for "negative logarithm." All logarithms are exponents. The pOH logarithm is a base-10 logarithm. The "base" is the number 10, the logarithm is the exponent. That means that 2 is the base-10 logarithm for 10², which equals 100. Since pH is a negative logarithm, a pOH of 2 is 10⁻² or 0.010. The capital letters OH stands for the molar concentration of the hydroxide ion (or OH⁻). So, a pH of 2 means the molar concentration of OH⁻ is 10⁻² M or 0.010 M.
What is an acid?
Arrhenius Theory: A substance that releases hydrogen ions (H⁺) in water. Bronsted-Lowry Theory: A substance that donates a hydrogen ion to form a covalent bond with another substance. Lewis Theory: A substance that accepts a pair of electrons to form a covalent bond. An acid is an aqueous solution that has a pH that is below 7.
What are bases?
Arrhenius Theory: A substance that releases hydroxide ions (OH⁻) in water. Brønsted-Lowry Theory: A substance that accepts a hydrogen ion to form a covalent bond with another substance. Lewis Theory: A substance that has a pair of electrons that it shares with another substance to form a covalent bond. A base is an aqueous solution that has a pH that is above 7.
What does pH mean?
Arrhenius Theory: The small letter p in pH stands for "negative logarithm." All logarithms are exponents. The pH logarithm is a base-10 logarithm. The "base" is the number 10, the logarithm is the exponent. That means that 2 is the base-10 logarithm for 10², which equals 100. Since pH is a negative logarithm, a pH of 2 is 10⁻² or 0.010. The capital letter H stands for the molar concentration of the hydrogen ion (or H⁺). So, a pH of 2 means the molar concentration of H⁺ is 10⁻² M or 0.010 M. Brønsted-Lowry Theory: Use hydronium (H₃O⁺) in place of the hydrogen ion (H⁺) that was used in the Arrhenius Theory.
How do you calculate the molar concentration of hydrogen ions from the pH?
Arrhenius Theory: To calculate the molar concentration of hydrogen ions from the pH, change the sign of the pH and make that negative number an exponent on the number 10. So, if the pH is 12.25, the molar concentration of hydrogen ions will be 10⁻¹²⸱²⁵ M or 5.623 ⨯ 10⁻¹³ M. Brønsted-Lowry Theory: Use hydronium (H₃O⁺) in place of the hydrogen ion (H⁺) that was used in the Arrhenius Theory.
What are the strong bases that you need to know?
Barium hydroxide - Ba(OH)₂ Calcium hydroxide - Ca(OH)₂ Lithium hydroxide - LiOH Potassium hydroxide - KOH Sodium hydroxide - NaOH Strontium hydroxide - Sr(OH)₂
What 2 weak acids form buffers that keep your blood pH around 7?
Carbonic acid - H₂CO₃ Phosphoric acid - H₃PO₄
Why are brackets used for [H₃O⁺], [H⁺], and [OH⁻]?
Chemists have agreed to use brackets to mean "molar concentration of." So, [H₃O⁺] means "the molar concentration of the hydronium ion," [H⁺] means "the molar concentration of the hydrogen ion," and [OH⁻] means "the molar concentration of the hydroxide ion." Molar concentration is the moles of a substance in one liter of that solution.
What is deprotonization?
Deprotonization refers to the removal of a hydrogen ion (also called a proton) when an acid is dissolved in water.
How are pH and pOH related?
For any solution at room temperature, pH + pOH = 14.00.
How do you calculate the pH from the pOH?
For any solution at room temperature, pH + pOH = 14.00. So, pH is calculated by subtracting the pOH from 14.00. So if the pH is 5.75, the pH is 14.00 - 5.75 = 8.25.
How do you calculate the pOH from the pH?
For any solution at room temperature, pH + pOH = 14.00. So, pOH is calculated by subtracting the pH from 14.00. So if the pH is 3.50, the pOH is 14.00 - 3.50 = 10.50.
What is the Brønsted-Lowry Theory symbolic equation that shows how acids dissociate in water?
HA(?) + H₂O(𝓵) → H₃O⁺(aq) + A⁻(aq)
What is the Arrhenius Theory symbolic equation that shows how acids dissociate in water?
HA(?) → H⁺(aq) + A⁻(aq)
What are the strong acids that you need to know?
Hydrobromic acid - HBr Hydrochloric acid - HCl Hydroiodic acid - HI Nitric acid - HNO₃ Chloric acid - HClO₃ Perchloric acid - HClO₄ Sulfuric acid - H₂SO₄
Why does hydroiodic acid have 1 dissociation equation?
Hydroiodic acid (HI) has 1 dissociation equation because it has 1 ionizable hydrogen atoms. Arrhenius Theory: HI(aq) → H⁺(aq) + I⁻(aq) Bronsted-Lowry Theory: HI(aq) + H₂O → H₃O⁺(aq) + I⁻(aq)
What are the weak bases?
If a base is no one of the strong acids, you can consider it to be a weak base.
How do you calculate the [OH⁻] from the [H⁺] or the [H₃O⁺]?
In the Brønsted-Lowry Theory, since Kw = [H₃O⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M², then the [OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M² /[H₃O⁺] . In other words, the molar concentration of the hydroxide ion is equal to the autoionization constant for water divided by the molar concentration of the hydronium ion. In the Arrhenius Theory, since Kw = [H⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M², then the [OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M² / [H⁺] . In other words, the molar concentration of the hydroxide ion is equal to the autoionization constant for water divided by the molar concentration of the hydrogen ion.
What kinds of acids have more that one dissociation equation?
Polyprotic acids.
How do you calculate the [H⁺] from the [OH⁻]?
Since Kw = [H⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M², then the [H⁺] = 1.00 x ⨯ 10⁻¹⁴ M² / [OH⁻] . In other words, the molar concentration of the hydrogen ion is equal to the autoionization constant for water divided by the molar concentration of the hydroxide ion.
How do you calculate the [H₃O⁺] from the [OH⁻]?
Since Kw = [H₃O⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M², then the [H₃O⁺] = 1.00 x ⨯ 10⁻¹⁴ M² / [OH⁻] . In other words, the molar concentration of the hydronium ion is equal to the autoionization constant for water divided by the molar concentration of the hydroxide ion.
Bronsted-Lowry Theory: What kind of base does a strong acid always produce?
Strong acids produce weak bases. So for a Bronsted-Lowry acid as illustrated in this general equation: HA(?) + H₂O(𝓵) → H₃O⁺(aq) + A⁻(aq) ...the weak base is what results when the hydrogen ion (H⁺) is dissociated from the acid. Therefore, A⁻ is a weak base if HA is a strong acid. For sulfuric acid (which is a real Bronsted-Lowry strong acid) the dissociation equation looks like this: H₂SO₄(aq) + H₂O → H₃O⁺(aq) + HSO₄⁻(aq) So, since H₂SO₄ (sulfuric acid) is a strong acid, the weak base is what results when the hydrogen ion (H⁺) is dissociated from the acid, HSO₄⁻ (hydrogen sulfate or bisulfate) is the weak base.
Why does sulfurous acid have 2 dissociation equations?
Sulfurous acid (H₂SO₃) has 2 dissociation equations because it has 2 ionizable hydrogens. Arrhenius Theory: H₂SO₃(aq) → H⁺(aq) + HSO₃⁻(aq) HSO₃⁻(aq) → H⁺(aq) + SO₃²⁻(aq) Bronsted-Lowry Theory: H₂SO₃(aq) + H₂O → H₃O⁺(aq) + HSO₃⁻(aq) HSO₃⁻(aq) + H₂O → H₃O⁺(aq) + SO₃²⁻(aq)
In titration chemistry, what is the analyte?
The analyte is the solution of UNKNOWN concentration for which titration and titration stoichiometry are used to determine the concentration.
How do you calculate the pH from the molar concentration of hydrogen ions?
This is part of the Arrhenius Theory. To calculate the pH from the molar concentration of hydrogen ions, you take the logarithm of the number and change the sign. If the molar concentration of hydrogen ions is 1.78 ⨯ 10⁻⁵ M, click the logarithm button on your calculator, enter that number, and change the sign. So, the pH is -LOG(1.78 ⨯ 10⁻⁵) OR -LOG(1.78E⁻5) and the answer is 4.75.
What is the autoionization constant for water?
The autoionization constant for water is symbolized as Kw. This is also called the "ion product constant for water" or the "dissociation constant for water." In the Arrhenius Theory, it is calculated by multiplying the molar concentration of the hydrogen ion [H⁺] by the molar concentration of the hydroxide ion [OH⁻]. In a math style equation, it looks like this: Kw = [H⁺][OH⁻]. In the Brønsted-Lowry Theory, it is calculated by multiplying the molar concentration of the hydronium ion [H₃O⁺] by the molar concentration of the hydroxide ion [OH⁻]. In a math style equation, it looks like this: Kw = [H₃O⁺][OH⁻] For any solution at room temperature, Kw always equals 1.00 x ⨯ 10⁻¹⁴ M². In a math style equation n the Arrhenius Theory, it looks like this: Kw = [H⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M². In a math style equation n the Brønsted-Lowry Theory, it looks like this: Kw = [H₃O⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M².
In titration chemistry, what is the endpoint?
The endpoint of a titration is the point where the indicator just changes color or the pH probe indicates that the pH for the equivalence point is reached. The equivalence point is when the ratio of reactants is in the amounts specified by the balanced chemical equation.
What is the ion product constant for water?
The ion product constant for water is symbolized as Kw. This is also called the "autoionization constant for water" or the "dissociation constant for water.". In the Arrhenius Theory, it is calculated by multiplying the molar concentration of the hydrogen ion [H⁺] by the molar concentration of the hydroxide ion [OH⁻]. In a math style equation, it looks like this: Kw = [H⁺][OH⁻]. In the Brønsted-Lowry Theory, it is calculated by multiplying the molar concentration of the hydronium ion [H₃O⁺] by the molar concentration of the hydroxide ion [OH⁻]. In a math style equation, it looks like this: Kw = [H₃O⁺][OH⁻] For any solution at room temperature, Kw always equals 1.00 x ⨯ 10⁻¹⁴ M². In a math style equation n the Arrhenius Theory, it looks like this: Kw = [H⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M². In a math style equation n the Brønsted-Lowry Theory, it looks like this: Kw = [H₃O⁺][OH⁻] = 1.00 x ⨯ 10⁻¹⁴ M².
What is titration stoichiometry?
The math is chemistry that depends on a molar ratio from a balanced chemical equation (stoichiometry) and which allows the chemist to determine the concentration of an acid or base (starting with the titrant volume from the titration).
What is/are the dissociation equation(s) for phosphoric acid?
The name phosphoric acid has no "hydro-" prefix so it must be made of one or more hydrogen ions attached to a polyatomic ion. Phosphoric comes from the phosphate ion. So, 3H⁺ + PO₄³⁻ → H₃PO₄ . Since phosphoric acid has 3 ionizable hydrogens, there are 3 dissociation equations: Arrhenius Theory: H₃PO₄(aq) → H⁺(aq) + H₂PO₄⁻(aq) H₂PO₄⁻(aq) → H⁺(aq) + HPO₄²⁻(aq) HPO₄²⁻(aq) → H⁺(aq) + PO₄³⁻(aq) Bronsted-Lowry Theory: H₃PO₄(aq) + H₂O → H₃O⁺(aq) + H₂PO₄⁻(aq) H₂PO₄⁻(aq) + H₂O → H₃O⁺(aq) + HPO₄²⁻(aq) HPO₄²⁻(aq) + H₂O → H₃O⁺(aq) + PO₄³⁻(aq)
What is a neutralization reaction?
The reaction of an acid and a base forming a salt and water
In titration chemistry, what is the titrant?
The titrant is the solution of whose concentration is KNOWN and which is dripped into the analyte until an endpoint (or equivalence point) is reached to stoichiometrically determine the concentration.
How do you calculate the pH from the molar concentration of hydronium (H₃O⁺) ions?
This is part of the Brønsted-Lowry Theory. To calculate the pH from the molar concentration of hydronium ions, you take the logarithm of the number and change the sign. If the molar concentration of hydronium ions is 1.78 ⨯ 10⁻⁵ M, click the logarithm button on your calculator, enter that number, and change the sign. So, the pH is -LOG(1.78 ⨯ 10⁻⁵) OR -LOG(1.78E⁻5) and the answer is 4.75.
What is titration?
Titration is the slow addition of one solution of a known concentration (called a titrant) to a known volume of another solution of unknown concentration (called the analyte) until the reaction reaches neutralization, which is often indicated by a color change or by using a pH probe. In a broad sense, titration is a technique to determine the concentration of an unknown solution.
To a chemist, what is a strong acid?
To a chemist, a strong acid is a substance with hydrogen ions that COMPLETELY dissociate from an anion in a liquid. An Arrhenius strong acid would do this... HA(?) → H⁺(aq) + A⁻(aq) with ALL of the HA changing to H⁺ and A⁻. An Bronsted-Lowrystrong acid would do this... HA(?) + H₂O(𝓵) → H₃O⁺(aq) + A⁻(aq) with ALL of the HA changing to H₃O⁺ and A⁻.
To a chemist, what is a weak acid?
To a chemist, a weak acid is a substance with hydrogen ions that DO NOT completely dissociate from an anion in a liquid. An Arrhenius strong acid would do this... HA(?) ⇄ H⁺(aq) + A⁻(aq) with SOME of the HA remaining in the solution with H⁺ and A⁻. A Bronsted-Lowrystrong acid would do this... HA(?) + H₂O(𝓵) ⇄ H₃O⁺(aq) + A⁻(aq) with SOME of the HA remaining in the solution along with H₃O⁺ and A⁻.
How do you calculate the molar concentration of hydroxide ions from the pOH?
To calculate the molar concentration of hydroxide ions from the pOH, change the sign of the pOH and make that negative number an exponent on the number 10. So, if the pOH is 2.25, the molar concentration of hydrogen ions will be 10⁻²⸱²⁵ M or 0.00532 M.
How do you calculate the pOH from the molar concentration of hydrogen ions?
To calculate the pOH from the molar concentration of hydroxide ions, you take the logarithm of the number and change the sign. If the molar concentration of hydroxide ions is 7.35 ⨯ 10⁻⁶ M, click the logarithm button on your calculator, enter that number, and change the sign. So, the pOH is -LOG(7.35 ⨯ 10⁻⁶) OR -LOG(7.35E⁻6) and the answer is 5.13.
How do you choose the best acid-base indicator for a titration?
You choose the indicator that begins to change color at the point where there is a stoichiometric equivalence of acid and base. This stoichiometric equivalence point is called the end point of the titration and is called the inflection point on the acid of base pH curve.
