Question

1. if a mass of 2.6 g of mercury is dissolved in 4 l of water, what is the concentration of mercury in ppm?

Explanation:

Step1: Convert the volume of water to mass

Assume the density of water is \(1\space g/mL\). Since \(1\space L = 1000\space mL\), then \(4\space L\) of water has a mass \(m_{water}=4\times1000 = 4000\space g\)

Step2: Use the ppm formula

The formula for parts - per - million (ppm) is \(ppm=\frac{m_{solute}}{m_{solution}}\times10^{6}\). Here, \(m_{solute}=2.6\space g\) and \(m_{solution}=m_{solute}+m_{water}\approx m_{water}\) (because \(m_{solute}\ll m_{water}\)).

Substitute the values into the formula: \(ppm=\frac{2.6}{4000}\times 10^{6}\)

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Answer:

\(650\)