H. Using the technique outlined in this lab, a student decided to test wastewater for the presence of phosphate. The first reading produced an extremely dark blue color and a concentration higher than 3ppm. After performing a 10 ml dilution, the colorimeter measured a resistance value of 580Ù.

1. Using the Figure 7 standard calibration curve, what was the phosphate concentration in the wastewater?

2. Phosphate plays an important role in fertilizers. It improves root growth and increases flower and fruit size. This student decided to use the wastewater to fertilize her garden. If the strawberries needed 0.022 grams of phosphate, how many L of the wastewater should be fed to the plant?

A colorimeter measured resistance?

Fig 7? You must think we are mind readers.