Structural Pest Control Applicator Practice Exam

How many milligrams per kilogram (mg/kg) are equivalent to parts per million?

1. One

2. Three

3. Six

4. Ten

The correct answer is: Six

The relationship between milligrams per kilogram (mg/kg) and parts per million (ppm) is based on the fact that one ppm is equivalent to one mg of substance per kilogram of total material. This means that 1 ppm is the same as 1 mg/kg under standard conditions, where the density of the solution is similar to that of water. Since there are 1,000,000 milligrams in a kilogram, converting mg/kg directly gives a 1:1 ratio for measurements of concentrations in dilute solutions. Therefore, it can be stated that one mg/kg is equivalent to one ppm. Consequently, the correct information is that one mg/kg translates directly to one ppm, and thus the answer of six is not a recognized standard in chemistry relating these two units. The value for ppm is straightforward and should firmly align with its equivalent in mg/kg, being one. This understanding is essential for anyone working in structural pest control or similar fields, where accurate measurements of chemical concentrations are key to maintaining safety and efficacy in applications.