Respuesta :
Answer: The concentration of calcium, magnesium, sodium and potassium are [tex]1.25\times 10^{-4}mol/L[/tex], [tex]4.20\times 10^{-5}mol/L[/tex], [tex]5.91\times 10^{-3}mol/L[/tex] and [tex]3.08\times 10^{-5}mol/L[/tex] respectively
Explanation:
To convert the mass from milligrams to grams, we use the conversion factor:
1 g = 1000 mg
To convert the given concentration fro grams to moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] .....(1)
- For Calcium:
Concentration given = 5.0 mg/L = [tex]5.0\times 10^{-3}g/L[/tex]
We know that:
Molar mass of calcium element = 40 g/mol
Putting values in equation 1, we get:
[tex]\text{Concentration in mol/L}=\frac{5.0\times 10^{-3}g/L}{40g/mol}\\\\\text{Concentration in mol/L}=1.25\times 10^{-4}mol/L[/tex]
- For Magnesium:
Concentration given = 1.0 mg/L = [tex]1.0\times 10^{-3}g/L[/tex]
We know that:
Molar mass of magnesium element = 24 g/mol
Putting values in equation 1, we get:
[tex]\text{Concentration in mol/L}=\frac{1.0\times 10^{-3}g/L}{24g/mol}\\\\\text{Concentration in mol/L}=4.20\times 10^{-5}mol/L[/tex]
- For Sodium:
Concentration given = 136 mg/L = [tex]136\times 10^{-3}g/L[/tex]
We know that:
Molar mass of sodium element = 23 g/mol
Putting values in equation 1, we get:
[tex]\text{Concentration in mol/L}=\frac{136\times 10^{-3}g/L}{23g/mol}\\\\\text{Concentration in mol/L}=5.91\times 10^{-3}mol/L[/tex]
- For Potassium:
Concentration given = 1.2 mg/L = [tex]1.2\times 10^{-3}g/L[/tex]
We know that:
Molar mass of potassium element = 39 g/mol
Putting values in equation 1, we get:
[tex]\text{Concentration in mol/L}=\frac{1.2\times 10^{-3}g/L}{39g/mol}\\\\\text{Concentration in mol/L}=3.08\times 10^{-5}mol/L[/tex]
Hence, the concentration of calcium, magnesium, sodium and potassium are [tex]1.25\times 10^{-4}mol/L[/tex], [tex]4.20\times 10^{-5}mol/L[/tex], [tex]5.91\times 10^{-3}mol/L[/tex] and [tex]3.08\times 10^{-5}mol/L[/tex] respectively
