Final answer:
One part per billion (ppb) is a measurement of solute concentration, equal to one part of solute in a billion parts of solution, and is calculated using the ratio [mass of solute/mass of solution] × 10⁹.
Step-by-step explanation:
The question is asking for the meaning of the term parts per billion (ppb), which is a unit of measurement used in chemistry to express the concentration of a substance in a solution. One part per billion means that there is one part of the substance, called the solute, in a billion parts of the entire solution. To calculate ppb, you can use the following formula: [mass of solute/mass of solution] × 10⁹ (µg solute/kg solution).
The correct option is:
This means that one part per billion is equivalent to one unit of solute for every billion units of solution, which expresses a ratio of solute-to-solution mass multiplied by 10⁹.