Structural Pest Control Applicator Practice Exam

How many gallons of 25 percent emulsifiable concentrate would you add to a 50 gallon tank to get a 1 percent active ingredient mixture?

1. 1.5 gallons

2. 2.075 gallons

3. 3 gallons

4. 4 gallons

The correct answer is: 2.075 gallons

To determine how many gallons of a 25 percent emulsifiable concentrate (EC) are needed to achieve a 1 percent active ingredient mixture in a 50-gallon tank, it's essential to set up the proper equations based on the principles of dilution and concentration. First, we need to understand that a 25 percent emulsifiable concentrate means that in every gallon of this concentrate, there are 0.25 gallons (or 25 percent) of active ingredient. When mixing this with a total volume of 50 gallons, we want to ensure that the final mixture has 1 percent active ingredient. This translates to needing 0.01 × 50 gallons = 0.5 gallons of active ingredient in the tank. Let’s denote the volume of the 25 percent emulsifiable concentrate to be added as ‘x’ gallons. The amount of active ingredient in this volume can be calculated as: - Active ingredient from the EC = 0.25 * x gallons. To achieve a final concentration of 0.5 gallons of active ingredient in the 50-gallon tank, we set up the equation: 0.25 * x = 0.5. Solving for x gives: x = 0.5 / 0.