Understanding Weak Bases

The video tutorial discusses weak bases, highlighting their incomplete dissociation compared to strong bases. It uses ammonia as a primary example, explaining its dissociation in water and the formation of conjugate acids and bases. The tutorial also covers the substitution of hydrogen in ammonia to form other weak bases like methylamine and dimethylamine. It provides a detailed explanation of calculating the pH of weak bases using ICE tables and equilibrium expressions, emphasizing the importance of checking assumptions in calculations.

Why are weak bases designated as 'weak'?

• They do not dissociate completely in water.

• They are all Arrhenius bases.

• They have no conjugate acids.

• They dissociate completely in water.

What is the classic example of a weak base discussed in the video?

• Sodium hydroxide

• Ammonia

• Sulfuric acid

• Hydrochloric acid

What ion is produced when ammonia dissociates in water?

• Hydroxide ion

• Hydronium ion

• Sulfate ion

• Chloride ion

What is the conjugate acid of ammonia?

• Methane

• Water

• Hydroxide ion

• Ammonium ion

What is the name of the molecule formed by substituting one hydrogen in ammonia with a methyl group?

• Methylamine

• Dimethylamine

• Methane

• Ethylamine

What does the 'amine' suffix in a molecule's name indicate?

• It is a strong base.

• It is derived from methane.

• It is derived from ammonia.

• It contains a hydroxide group.

What is the purpose of setting up an ICE table in pH calculations?

• To calculate the equilibrium concentrations of reactants and products.

• To determine the initial concentration of water.

• To measure the temperature of the solution.

• To find the molecular weight of the base.

What is the value of x in the ICE table for a weak base?

• The volume of the solution.

• The initial concentration of the base.

• The equilibrium constant of the base.

• The change in concentration of the base.

How do you calculate the pOH of a solution?

• By taking the negative log of the hydroxide ion concentration.

• By adding the hydroxide ion concentration to the pH.

• By multiplying the hydroxide ion concentration by 14.

• By taking the negative log of the hydronium ion concentration.

What should you do after calculating the pOH to find the pH?

• Subtract the pOH from 14.

• Divide the pOH by 14.

• Add the pOH to 14.

• Multiply the pOH by 14.