p.3
pH and Hydrogen Ion Concentration
How can pH be calculated?
pH = -log [H+], where [H+] is the concentration of H ions.
What is a buffer solution?
A solution that maintains a relatively constant pH when small amounts of acids or alkalis are added.
How is the pH expressed in terms of Ka and concentrations of acid and salt?
pH = pKa + log10([acid]/[salt]).
p.10
Ionic Product of Water (Kw)
What is the ionic product of water used for?
To find the concentration of OH⁻ ions in solution if [H⁺] is known.
p.8
Brønsted Acids and Bases
What happens to strong acids in solution?
They are completely ionized.
p.7
Acid Dissociation Constant (Ka) and pKa
What does a greater pK value indicate about an acid?
The acid is less strongly acidic.
p.16
Solubility Product (Ksp) and pKa
How much sodium chloride (NaCl) is present in a saturated solution?
36 g of NaCl per 100 g of water.
p.22
Solubility Product (Ksp)
What is the equilibrium reaction for CaSO₄?
CaSO₄ (s) ⇌ Ca²⁺ (aq) + SO₄²⁻ (aq)
p.5
Acid Dissociation Constant (Ka) and pKa
What is the equilibrium expression to find K for ethanoic acid?
K = [H⁺][CH₃COO⁻] / [CH₃COOH]
p.21
Solubility Product (Ksp)
What happens when potassium chloride is added to a saturated solution of silver chloride?
It results in the precipitation of silver chloride.
How can the concentration of hydrogen ions be determined from the equilibrium expression?
[H+] = Ka × [acid]/[salt].
p.4
Acid Dissociation Constant (Ka) and pKa
What is the relationship between pK and acidity?
The less positive the pK value, the more acidic the acid is.
p.6
Ionic Product of Water (Kw)
In pure water, what is the relationship between the concentrations of H⁺ and OH⁻?
The concentrations of H⁺ and OH⁻ are equal.
What is the role of HCO₃⁻ ions in the human body?
They act as a buffer to keep the blood pH between 7.35 and 7.45.
p.4
Acid Dissociation Constant (Ka) and pKa
What does a low value of K indicate about a weak acid?
The equilibrium position lies to the left, the acid is only slightly ionized, and it is weakly acidic.
p.3
Acid Dissociation Constant (Ka) and pKa
What does K_a represent?
The acidic dissociation constant.
p.9
Brønsted Acids and Bases
What is the dissociation equation for hydrochloric acid?
HCl (aq) → H+ (aq) + Cl- (aq)
What happens when H⁺ ions are added to a buffer solution?
The equilibrium shifts to the left, forming more CH₃COOH and maintaining pH.
p.18
Solubility Product (Ksp)
What is the solubility product (Ksp) of a compound?
It is the equilibrium constant for a saturated solution of a sparingly soluble ionic compound.
p.18
Solubility Product (Ksp)
How do you calculate the solubility product from solubility?
By using the equilibrium expression based on the dissociation of the compound in solution.
p.10
Conjugate Acid-Base Pairs
What is the ionization equation for sodium hydroxide?
NaOH (aq) → Na⁺ (aq) + OH⁻ (aq)
What is the relationship between the concentration of hydroxide ions and the concentration of a strong alkali?
[OH-] is equal to the concentration of the base [BOH].
Can buffer solutions cope with excessive addition of acids or alkalis?
No, their pH will change significantly with excessive addition.
What is the effect of a large reserve supply of CH₃COOH on its concentration in solution?
The concentration of CH₃COOH doesn't change much when it dissociates.
What is the equilibrium reaction for ethanoic acid in a buffer solution?
CH₃COOH (aq) ⇌ H⁺ (aq) + CH₃COO⁻ (aq).
p.3
pH and Hydrogen Ion Concentration
What does pH indicate?
The acidity or basicity of an acid or alkali.
p.7
Acid Dissociation Constant (Ka) and pKa
What does a greater K value indicate about an acid?
The acid is more strongly acidic.
p.13
Equilibrium Reactions
What happens to the equilibrium position if there is an increase in H⁺ ions?
The equilibrium position shifts to the left until equilibrium is restored.
p.8
Brønsted Acids and Bases
What is the total concentration of hydrogen ions in a strong acid solution?
It is the same as the concentration of the acid, [HA].
p.22
Solubility Product (Ksp)
Will a precipitate of CaSO₄ form when the solutions are mixed?
No, because the product of the ion concentrations (5.0 x 10⁻⁶ mol² dm⁻⁶) is smaller than the Ksp value (2.0 x 10⁻⁶ mol² dm⁻⁶).
p.1
Conjugate Acid-Base Pairs
How is ethanoic acid (CH₃COOH) related to its conjugate base?
CH₃COOH donates a proton to form CH₃COO⁻.
p.4
Acid Dissociation Constant (Ka) and pKa
What does a high value of K indicate about a weak acid?
The equilibrium position lies to the right, the acid is almost completely ionized, and it is strongly acidic.
p.4
Acid Dissociation Constant (Ka) and pKa
Why are pK values used instead of K values for weak acids?
Because K values of many weak acids are very low, making pK values more useful for comparison.
What does the dissociation of a weak acid imply about the concentrations of HA and A?
The concentration of HA is approximately the same as the concentration of A.
p.8
pH and Hydrogen Ion Concentration
How can pH be calculated from the concentration of hydrogen ions?
Using the equation: pH = -log [H+].
What components can a buffer solution consist of?
A weak acid and its conjugate base, or a weak base and its conjugate acid.
p.6
Ionic Product of Water (Kw)
What does the constant concentration of H₂O allow us to do in the equilibrium expression?
It allows us to simplify the expression by removing [H₂O].
p.6
Calculations Involving Acids, Bases, and Salts
What is the first step in calculating the concentration of H⁺ in pure water?
Write down the equation for the partial dissociation of water: H₂O (l) ⇌ H⁺ (aq) + OH⁻ (aq).
p.11
Equilibrium Reactions
What is the equilibrium expression for the dissociation of ethanoic acid?
K = [H+][CH3COO-] / [CH3COOH].
p.10
Acid Dissociation Constant (Ka) and pKa
What is required to calculate the pH of weak acids?
The concentration of the weak acid and its dissociation constant.
p.3
Acid Dissociation Constant (Ka) and pKa
What assumption is made when writing the equilibrium expression for weak acids?
The concentration of hydrogen ions due to the ionization of water is negligible.
p.1
Conjugate Acid-Base Pairs
What is a Brønsted acid?
A species that can donate a proton.
p.18
Solubility Product (Ksp)
How do you find the concentration of Pb2+ ions in the solution?
It is equal to the solubility of PbBr2, which is 1.39 x 10^-3 mol dm^-3.
p.17
Solubility Product (Ksp)
What is the K expression for Fe₂O₃?
K = [Fe³⁺ (aq)]² [O²⁻ (aq)]³
p.17
Solubility Product (Ksp)
What is the K expression for SnCO₃?
K = [Sn²⁺ (aq)] [CO₃²⁻ (aq)]
What is needed to calculate the pH of a buffer solution?
The Ka of the weak acid and the equilibrium concentration of the weak acid and its conjugate base (salt).
p.10
Ionic Product of Water (Kw)
How do you calculate the hydroxide ion concentration from pH?
Rearrange the ionic product of water: [OH⁻] = Kw / [H⁺]
p.15
Equilibrium Reactions
How do you find the concentration of hydrogen ions [H⁺]?
[H⁺] = K × [CH₃COOH] / [CH₃COO⁻].
p.22
Solubility Product (Ksp)
What is the equilibrium expression for Ksp of CaSO₄?
Ksp = [Ca²⁺ (aq)] [SO₄²⁻ (aq)]
p.22
Calculations Involving Acids, Bases, and Salts
What is the new concentration of Ca²⁺ after mixing the solutions?
[Ca²⁺] = 5.0 x 10⁻⁴ mol dm⁻³
p.17
Solubility Product (Ksp)
What is the balanced chemical equation for the solubility product of Ca(OH)₂?
Ca(OH)₂ (s) ⇌ Ca²⁺ (aq) + 2OH⁻ (aq)
What happens to blood pH if the concentration of H⁺ ions is not regulated?
The blood pH would drop, causing 'acidosis'.
p.13
Equilibrium Reactions
What is the equilibrium reaction involving CO₂ and H₂O in the blood?
CO₂ (g) + H₂O (l) ⇌ H⁺ (aq) + HCO₃⁻ (aq).
Why can the number of hydrogen ions formed from the ionization of water be neglected in strong acid solutions?
Because it is very small relative to the [H+] from the strong acid.
p.16
Solubility Product (Ksp) and pKa
What is the solubility of lead chloride (PbCl2) in a saturated solution?
0.99 g of PbCl2 per 100 g of water.
p.22
Calculations Involving Acids, Bases, and Salts
What is the concentration of SO₄²⁻ in the mixed solution?
[SO₄²⁻] = 1.0 x 10⁻³ mol dm⁻³
p.18
Solubility Product (Ksp)
How do you calculate the concentration of Br- ions from the solubility of PbBr2?
Br- concentration is 2 times the solubility of PbBr2, resulting in 2.78 x 10^-3 mol dm^-3.
What occurs in an equilibrium reaction?
Products are formed at the same rate as reactants are used.
p.19
Solubility Product (Ksp)
Which types of salts should not be analyzed using the solubility product?
Soluble salts such as Group 1 element salts, all nitrate salts, and many sulfate salts.
p.8
pH and Hydrogen Ion Concentration
How can the concentration of hydrogen ions be calculated from pH?
By rearranging the equation to: [H+] = 10^(-pH).
p.8
Brønsted Acids and Bases
What is the relationship between the concentration of hydrogen ions and the concentration of the acid for strong acids?
The concentration of hydrogen ions ([H+]) is equal to the concentration of acid ([HA]).
p.5
Acid Dissociation Constant (Ka) and pKa
What is the equation for the partial dissociation of ethanoic acid?
CH₃COOH (aq) ⇌ H⁺ (aq) + CH₃COO⁻ (aq)
p.13
Equilibrium Reactions
What happens to the equilibrium position if there is a decrease in H⁺ ions?
The equilibrium position shifts to the right until equilibrium is restored.
What happens when OH⁻ ions are added to a buffer solution?
The OH⁻ reacts with H⁺ to form water, causing the equilibrium to shift right and more CH₃COOH to ionize.
What is the role of sodium ethanoate in a buffer solution?
It fully ionizes in solution to provide a high concentration of ethanoate ions.
p.18
Solubility Product (Ksp)
What is the equilibrium equation for lead(II) bromide (PbBr2)?
PbBr2 (s) ⇌ Pb2+ (aq) + 2Br- (aq)
p.19
Solubility Product (Ksp)
How is the equilibrium expression for the solubility product written for CuO?
K = [Cu²⁺ (aq)] [O²⁻ (aq)].
What is a common buffer solution involving ethanoic acid?
An aqueous mixture of ethanoic acid and sodium ethanoate.
p.16
Solubility Product (Ksp) and pKa
What is the definition of solubility?
The number of grams or moles of a compound needed to saturate 100 g of water at a given temperature.
How does ethanoic acid behave in solution?
It is a weak acid that partially ionizes to form a low concentration of ethanoate ions.
p.11
Equilibrium Reactions
How can the equilibrium expression for ethanoic acid be simplified?
K = [H+]^2 / [CH3COOH] because the ratio of H+ to CH3COO- ions is 1:1.
p.16
Equilibrium Reactions
What happens when an undissolved ionic compound is in contact with a saturated solution?
An equilibrium is established where ions move from the solid to the solution at the same rate as they move from the solution to the solid.
p.17
Solubility Product (Ksp)
What is the K expression for Ca(OH)₂?
K = [Ca²⁺ (aq)] [OH⁻ (aq)]²
p.17
Solubility Product (Ksp)
What is the balanced chemical equation for the solubility product of Fe₂O₃?
Fe₂O₃ (s) ⇌ 2Fe³⁺ (aq) + 3O²⁻ (aq)
p.17
Solubility Product (Ksp)
What is the balanced chemical equation for the solubility product of SnCO₃?
SnCO₃ (s) ⇌ Sn²⁺ (aq) + CO₃²⁻ (aq)
p.19
Equilibrium Reactions
What is the equilibrium equation for the dissolution of copper(II) oxide?
CuO (s) ⇌ Cu²⁺ (aq) + O²⁻ (aq).
What is acidosis?
A condition in which there is too much acid in the body fluids such as blood.
p.15
Equilibrium Reactions
What is the equilibrium expression for calculating K?
K = [CH₃COO⁻][H⁺] / [CH₃COOH].
p.16
Solubility Product (Ksp)
What does the solubility product (Ksp) represent?
The product of the concentrations of each ion in a saturated solution of a relatively soluble salt.
p.16
Solubility Product (Ksp)
What is the equilibrium expression for a saturated solution of a salt?
Ksp = [A(aq)]^a [B(aq)]^b.
p.16
Equilibrium Reactions
What is the equilibrium expression for magnesium chloride (MgCl2)?
MgCl2(s) ⇌ Mg(aq) + 2Cl(aq).
p.1
Conjugate Acid-Base Pairs
What is a conjugate acid-base pair?
Two species that differ by one H⁺ ion.
What ions are present when ethanoic acid reaches equilibrium in solution?
CH₃COOH, H₂O, CH₃COO⁻, and H⁺ ions.
p.19
Solubility Product (Ksp)
What types of salts is the solubility product applicable to?
Very slightly soluble salts.
How can the pH of a strong alkali be calculated?
Using the ionic product of water: Kw = [H+][OH-].
p.9
Ionic Product of Water (Kw)
What is the value of Kw at 25°C?
1.00 x 10^-14 mol^2 dm^-6
p.18
Solubility Product (Ksp)
What is the calculated value of the solubility product (Ksp) for lead(II) bromide?
1.07 x 10^-8 mol^3 dm^-9.
p.1
Conjugate Acid-Base Pairs
What is the relationship between acids and bases in terms of proton transfer?
Acids donate protons, while bases accept protons.
p.19
Equilibrium Reactions
What simplification can be made in the equilibrium expression for CuO?
Since the ratio of Cu²⁺ to O²⁻ is 1:1, K = [Cu²⁺ (aq)].
