Question

A water utility uses a \(0.8 \%\) sodium hypochlorite solution to disinfect a well. What is the ppm concentration of the solution?

Short answer

8,000 ppm

Step-by-step solution

Understand the Relationship Between Percentage and PPM

Parts per million (ppm) and percentage are both ways to express concentration. 1% is equivalent to 10,000 ppm.

Convert Percentage to PPM

Use the relationship: \[ 1\text{ %} = 10,000 \text{ ppm} \] Thus, for a 0.8% solution: \[ 0.8\text{ %} = 0.8 \times 10,000 \text{ ppm} \]

Calculate the Result

Perform the multiplication: \[ 0.8 \times 10,000 = 8,000 \text{ ppm} \]

Key concepts

sodium hypochlorite solution

Sodium hypochlorite (NaOCl) is widely used as a disinfectant in water treatment. It's the active ingredient in common household bleach. When you see a sodium hypochlorite solution, it's essentially a mixture of the chemical in water. This mixture is used for disinfecting because it releases chlorine, which kills bacteria, viruses, and other pathogens.

Sodium hypochlorite is chosen for its effectiveness and ease of use. It can be simply added to water, and the concentration can be easily adjusted. In water treatment scenarios, a specific concentration—a sodium hypochlorite solution, in this case—is used to ensure the water is safe to drink.

It's important to note the concentration of sodium hypochlorite when used for disinfection. Concentration is often expressed as a percentage. In this exercise, we deal with a 0.8% solution, a common strength for water disinfection needs.

percentage to ppm

To understand and work with concentrations, it's often necessary to convert between percentage (%) and parts per million (ppm). Both are ways of indicating how much of one substance (like sodium hypochlorite) is present in a mixture (like water).

Here's how the conversion works:

• 1% means 1 part of the substance in 100 parts of the solution.
• Parts per million (ppm) provides this ratio on a much finer scale, where 1% equates to 10,000 ppm.

This relationship can be used to make conversions straightforward. For a 0.8% sodium hypochlorite solution, the concentration in ppm can be found by multiplying the percentage by 10,000:

0.8% × 10,000 ppm/% = 8,000 ppm

This means that a 0.8% sodium hypochlorite solution is equivalent to 8,000 ppm, making it easier to measure small quantities precisely.

water disinfection calculation

Water disinfection is a crucial step in ensuring that drinking water is safe. Sodium hypochlorite is often used due to its effectiveness in killing harmful microorganisms. Calculating the proper concentration for disinfection involves understanding how much sodium hypochlorite is required.

To determine the necessary concentration, water utilities often start with the known percentage solution of sodium hypochlorite. For instance, if you have a 0.8% solution, you may need to convert this to ppm to match standard requirements or guidelines for safe disinfection levels.

The conversion performed in the exercise—from 0.8% to 8,000 ppm—helps determine how much of the substance will be effective in the water. Knowing the ppm concentration ensures precise control over the disinfection process, enabling the water utility to achieve the desired level of disinfection reliably.

By understanding these calculations, water treatment professionals can ensure they are adding the correct amount of sodium hypochlorite, which helps protect public health. Practical knowledge in converting and calculating concentrations is essential for anyone involved in water treatment and disinfection.