Calculating the Hardness of Water Sample Containing Magnesium Sulfate
When dealing with water analysis, determining the hardness of a water sample is crucial. In this article, we explore the methodology to calculate the hardness of a water sample that contains a specific amount of magnesium sulfate (MgSO4). We will guide you through the steps to find the hardness in parts per million (ppm), a common unit for water hardness measurements.
Understanding the Molar Mass of MgSO4
To initiate the process, we need to determine the molar mass of magnesium sulfate. The molar mass of MgSO4 is calculated as follows:
Magnesium (Mg) 24.31 g/mol Sulfur (S) 32.07 g/mol Oxygen (O) 16.00 g/mol (x4) 64.00 g/molThe molar mass of MgSO4 is:
Molar mass of MgSO4 24.31 32.07 64.00 120.38 g/mol
Calculating the Mass of MgSO4
Given that there are 0.002 moles of MgSO4 in one liter of water, we can calculate the mass of MgSO4 in grams as follows:
Mass of MgSO4 moles × molar mass
Mass of MgSO4 0.002 moles × 120.38 g/mol 0.24076 g
Next, we convert this mass to milligrams since 1 ppm is equivalent to 1 mg/L:
0.24076 g 240.76 mg
Converting to Parts Per Million (ppm)
The hardness of the water sample in ppm can now be determined:
Hardness ppm 240.76 ppm
Therefore, the water sample containing 0.002 moles of MgSO4 per liter of water has a hardness of approximately 240.76 ppm.
Alternative Method for Hardness Calculation
Another perspective on calculating hardness involves relating the mass of MgSO4 to CaCO3, a common method in water quality analysis. If 0.001 moles of MgSO4 equals 0.12 grams (120 mg) in one liter of solution, we can correlate this to CaCO3:
1000 grams of H2O contain 120 mg of MgSO4.
1,000,000 grams of H2O (1 liter) will contain 120 grams of MgSO4.
Since 1 mole of MgSO4 is equivalent to 1 mole of CaCO3, the calculated mass of MgSO4 is 120 grams, which corresponds to 100 grams of CaCO3.
This indicates that the hardness of the water will be 100 ppm.
Conclusion
Both methods provide a clear and accurate way to determine the hardness of water samples based on the dissolved magnesium sulfate content. Understanding the hardness of water is critical for various applications, from domestic use to industrial processes. By employing these calculations, you can ensure that your water quality meets the necessary standards.