Question

How many parts per million (ppm) does a concentration of 0.01% represent ?

• A. 1 ppm
• B. 10 ppm
• C. 100 ppm
• D. 1000 ppm

Hint:

To convert any percentage (%) concentration to parts per million (ppm), simply move the decimal point four places to the right.
For example, \(0.01\% \rightarrow 0.1 \rightarrow 1.0 \rightarrow 10.0 \rightarrow 100\text{ ppm}\).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Concentration expressions in chemistry and water quality management can be represented in percentage (%) or in parts per million (ppm).
Both units express the ratio of solute to the total volume or mass of the solution.
Key Formula or Approach:
The conversion relationship between percentage (%) and parts per million (ppm) is defined as:
\[ 1\% = 10,000\text{ ppm} \]
This relationship is derived because a percentage is parts per hundred (\(10^{-2}\)), and ppm is parts per million (\(10^{-6}\)).
To convert a percentage concentration to ppm, use the formula:
\[ \text{Concentration (ppm)} = \text{Concentration (\%)} \times 10,000 \]

Step 2: Detailed Explanation:
Let us perform the calculation with the given value:
The given concentration is:
\[ \text{Concentration} = 0.01\% \]
Multiply this percentage by 10,000 to convert it to ppm:
\[ \text{Concentration (ppm)} = 0.01 \times 10,000 \]
\[ \text{Concentration (ppm)} = 100\text{ ppm} \]
Therefore, a concentration of 0.01% represents 100 ppm, which is equivalent to 100 milligrams of solute per liter of water (100 mg/L).

Step 4: Final Answer:
A concentration of 0.01% is equivalent to 100 ppm, which corresponds to Option (C).