The active volcano Mauna Loa, in Hawaii, and the now-extinct volcano Ei Yunque. Puerto Rico, have certain basaltic lava rocks containing the element selenium. Typically, a 25-g rock contains 0.005 g of selenium. What is the concentration of selenium in these lava rocks, in ppm?
To calculate the concentration of selenium in these lava rocks in parts per million (ppm), we can use the formula:
Concentration (ppm) = (Mass of selenium in rock / Mass of rock) * 1,000,000
Given:
Mass of selenium in rock = 0.005 g
Mass of rock = 25 g
Plugging in the values:
Concentration (ppm) = (0.005 g / 25 g) * 1,000,000
Concentration (ppm) = (0.0002) * 1,000,000
Concentration (ppm) = 200 ppm
Therefore, the concentration of selenium in these lava rocks is 200 ppm.