Week 4: STPP Equivalent Weight

What is the function of STPP in detergents?

STPP softens water, enhances detergent cleaning power, and prevents dirt re-deposition.

How do surfactants remove grease?

The hydrophobic tails attach to grease, forming micelles that allow grease to be washed away by water.

Why is STPP harmful to the environment?

It contributes to eutrophication by increasing phosphate levels in water, leading to excessive algae growth and oxygen depletion.

What is the purpose of the titration experiment in STPP analysis?

To determine the phosphate content in detergents by titrating STPP hydrolysis products.

How do you calculate the equivalent weight of an acid?

Equivalent weight = Molecular weight ÷ Number of equivalents of H⁺ or OH⁻.

• Example:

• H₂SO₄ molecular weight = 98.07 g/mol.

• H₂SO₄ donates 2 acidic protons.

• Equivalent weight = 98.07 g / 2 = 49.04 g/equivalent.

How to you calculate the Normality (N) of an acid/ base?

Similar to normality (N):

• Normality = Molarity × Equivalents of H⁺ or OH⁻.