Chapter 10 :Acids and Bases

1- concepts cides/ base

• what is a acides/ base what is a Conjugate acides/ base?
• , how to write equations to acid and Conjugate base?

10.1 Bronsted-Lowry definition for acids and bases
10.2 Lewis definition for acids and bases

there is two main theories call “base acis tyiory” one is bronsted theory and one is lewis theory.

it ie writen from left to right , there is more hydrogen in left side

call : “strong acides/ base” , and some change gradually antil to equilibrium point called “weak acides/ base”

some of the bases / acids so potent that they complete the conversion fully.

list of strong bases
electrolytes basis:

Acidic oxides, basic oxides and amphoteric oxides

alkali metal + hydroxide :

Na-oh k-oh li-oh Rb-oh

molecular basis

strong acids

2- how to calculate the changing in the concentration of “strong acides/ base”?

the aquations is ionic equation: HA(aq) + OH⁻(aq) → A⁻(aq) + H₂O(l)

one to strong base conversion fully in one direction so we don’t need to make a equilibrium table

but if

is initial concentration chang to

3 how to caculate the PH in water

1. Understand pH and pOH:
   • pH is a measure of the acidity or basicity of a solution and is defined as the negative logarithm (base 10) of the concentration of hydronium ions ([H₃O⁺]).
   • pOH is a measure of the concentration of hydroxide ions ([OH⁻]) in a solution and is defined as the negative logarithm (base 10) of the concentration of hydroxide ions.
2. Determine the Concentrations:
   • If you’re given the concentration of hydroxide ions ([OH⁻]), you can calculate pOH using the formula: pOH = -log[OH⁻].
   • If you’re given the concentration of hydronium ions ([H₃O⁺]), you can calculate pH using the formula: pH = -log[H₃O⁺].
3. Calculate pH or pOH:
   • If you’ve calculated pOH from the given [OH⁻], you can find pH using the relationship: pH + pOH = 14 (at 25°C).
   • If you’ve calculated pH from the given [H₃O⁺], you don’t need to do any additional calculations.
4. Example Calculation: Let’s say you’re given the concentration of hydroxide ions [OH⁻] as 1.0 x 10⁻⁵ M.
   • Calculate pOH: pOH = -log(1.0 x 10⁻⁵) = 5.
   • Since pH + pOH = 14, pH = 14 – pOH = 14 – 5 = 9.
5. Consider Temperature:
   • The relationship between pH and pOH (pH + pOH = 14) holds true at 25°C. At different temperatures, the relationship may vary slightly due to the autoionization of water.
6. Interpret the Result:
   • A pH value less than 7 indicates an acidic solution.
   • A pH value greater than 7 indicates a basic (alkaline) solution.

To write a homogeneous equilibrium equation, you need to understand what homogeneous equilibrium is and how it differs from heterogeneous equilibrium.

Homogeneous equilibrium occurs in a system where all reactants and products are in the same phase. For example, if all substances in a chemical reaction are in the gas phase or all in the aqueous phase (dissolved in water), it’s a homogeneous system. On the other hand, heterogeneous equilibrium involves reactants and products in different phases, such as a gas reacting with a solid.

1. Here, K is the equilibrium constant, and the square brackets represent the concentrations (or partial pressures) of the substances involved.
2. Substitute Concentrations or Pressures: Substitute the concentrations (for aqueous solutions) or partial pressures (for gases) of the reactants and products into the equilibrium expression. These concentrations or pressures are typically given in the problem or need to be calculated.
3. Simplify if Necessary: Simplify the equilibrium expression by substituting numerical values for the concentrations or pressures if known. Otherwise, leave the expression in terms of variables and known constants.
4. Write the Homogeneous Equilibrium Equation: Write the final equilibrium expression, including any numerical values if available. Ensure that the equation represents the equilibrium state of the homogeneous system based on the concentrations or partial pressures.
5. Check Units and Consistency: Verify that the units of concentrations or pressures used in the equilibrium expression are consistent and appropriate for the phase of the substances (e.g., moles per liter for aqueous solutions, atmospheres for gases).

Following these steps will help you write a homogeneous equilibrium equation accurately based on the phase of the substances involved and the law of mass action.

4- how to use the valiu of Ka to determine the potential of the acid

5- Ice Tables to calaulate PH in Polyprotic Acid Base Equilibria : K1,2,3,

An ICE table, which stands for Initial, Change, and Equilibrium, is a useful tool in solving equilibrium problems, including those involving polyprotic acid-base equilibria. Polyprotic acids are substances that can donate multiple protons (hydrogen ions) in sequential steps. Examples include phosphoric acid (H₃PO₄) and carbonic acid (H₂CO₃).

By following these steps and using an ICE table, you can effectively calculate the pH in polyprotic acid-base equilibria. It’s important to keep track of units, assumptions made, and the validity of approximations, especially when dealing with successive dissociation steps.

Here are the steps to write a homogeneous equilibrium equation:

1. Write the Balanced Chemical Equation: Start by writing the balanced chemical equation for the reaction that is occurring in the homogeneous system. Make sure the equation is balanced in terms of atoms and charges.
2. Determine the State of Matter: Identify the state of matter for each reactant and product. For a homogeneous equilibrium, all substances should be in the same phase (e.g., gas or aqueous).
3. Write the Equilibrium Expression:
   • For a gas-phase homogeneous equilibrium, use the partial pressures of gases in the equilibrium expression.
   • For an aqueous-phase homogeneous equilibrium, use the concentrations of dissolved species (ions or molecules) in the equilibrium expression.
4. Apply the Law of Mass Action: Use the law of mass action to write the equilibrium expression based on the balanced chemical equation. The general form of the equilibrium expression for a reaction

Here’s how you can use an ICE table to calculate pH in a polyprotic acid-base equilibrium:

1. Write the Balanced Equation: Start by writing the balanced chemical equation for the polyprotic acid and its dissociation into ions. For example, let’s use phosphoric acid (H₃PO₄) as an example:

Set Up the ICE Table: Create a table with columns for Initial concentration, Change in concentration, and Equilibrium concentration. For a polyprotic acid like H₃PO₄, you’ll have multiple rows in the ICE table corresponding to each proton dissociation step.

Apply the Equilibrium Constant Expression: Write the equilibrium constant expression for each dissociation step. For phosphoric acid, the equilibrium constant for the first dissociation step is

2. etermine Initial Concentrations and Known Values: Fill in the initial concentrations based on the information given in the problem. For example, if you’re given the initial concentration of H₃PO₄, fill it in as [H₃PO₄]₀. If you’re given the pH, you can calculate the initial concentration of H₃PO₄ using the pH equation.

3. Calculate Changes and Equilibrium Concentrations: Use the ICE table to determine the changes in concentration (x) and the equilibrium concentrations for each species. You may need to make assumptions about the relative magnitudes of x for each dissociation step based on the acid’s pKa values.

4. Set Up the Equilibrium Constant Expression: Substitute the equilibrium concentrations into the equilibrium constant expression for each step. For phosphoric acid, this would involve calculating

5. Solve for x: Use algebraic methods to solve for x, which represents the concentration of H⁺ ions (or H₃O⁺ ions) at equilibrium. This concentration is related to the pH of the solution.

6. Calculate pH: Once you have the concentration of H⁺ ions (or H₃O⁺ ions), you can use the pH formula: pH = -log[H⁺] (or pH = -log[H₃O⁺]) to determine the pH of the solution.

7. Consider Additional Dissociation Steps (if applicable): For polyprotic acids like phosphoric acid, there may be additional dissociation steps. Repeat the ICE table and calculations for each successive dissociation step to determine the overall pH of the solution accurately.

drop the X

to drop the X beneath we need a drop test

6- how to determine the concentration in the next protonation

7- calculate PH in amphiprotic :(1/2)(pKa1+pKa2)