Question

1. a concentration of 344 ppm of cadmium is found in a body of water with a mass of 67.8 kg. how much cadmium is in the water? (2)

Explanation:

Step1: Convert ppm to decimal

Parts per million (ppm) is equivalent to \( \frac{mg}{kg} \). So, \( 344\ ppm=\frac{344\ mg}{1\ kg}=344\times10^{- 3}\ g/kg = 0.344\ g/kg\)

Step2: Calculate the mass of cadmium

We know the formula \(m_{\text{solute}}=\text{concentration}\times m_{\text{solution}}\). Given \(m_{\text{solution}} = 67.8\ kg\) and concentration \(c = 0.344\ g/kg\)

\(m_{\text{Cd}}=0.344\ g/kg\times67.8\ kg\)

\(m_{\text{Cd}}=(0.344\times67.8)\ g\)

\(m_{\text{Cd}} = 23.3\ g\)

Answer:

The mass of cadmium in the water is \(23.3\ g\)