Question

In: Civil Engineering

if the concentration of Mg2+ in water is 36.6 mg/L, what is the hardness of the...

if the concentration of Mg2+ in water is 36.6 mg/L, what is the hardness of the water aa mg/L CaCO3?

Solutions

Expert Solution

Given, concentration of in water = 36.6 mg/L

We know that, hardness is due to the presence of multivalent cations in water and its total concentration will give the hardness of water. is one such cation.

Therefore,

Hardness of water = concentration of

But, we are asked to determine this in terms of mg/L of

This shall be done as follows:

Or

To avoid lengthy calculations we can just multiply given concentration of by a factor of 4.1 to convert it in terms of .

Hence, hardness of water = 150.62 mg/L as CaCO3.


Related Solutions

A chemical analysis of a surface water yields the following data: Ion      Concentration (mg/L) Ca2+ 90 Mg2+...
A chemical analysis of a surface water yields the following data: Ion      Concentration (mg/L) Ca2+ 90 Mg2+ 30 Na+ 72 K+ 6 Cl- 120 SO42- 225 HCO3- 165 pH 7.5 What concentration of Cl- (mg/L) would make the cations and anions balance?  
Given a water sample with the following concentrations, calculate the hardness in meq/L and mg/L as...
Given a water sample with the following concentrations, calculate the hardness in meq/L and mg/L as CaCO3 Ca2+= 17 mg/L CO32-= 3.4 mg/L
1. The results of a water analysis are as follows: Ca2+ = 70 mg/L Mg2+ =...
1. The results of a water analysis are as follows: Ca2+ = 70 mg/L Mg2+ = 9.7 mg/L Na+ = 6.9 mg/L K + = 0.1 mg/L Cl- = 10.6 mg/L SO4 2- = 96.0 mg/L HCO3 - = 140.3 mg/L 1) Is this an acceptable analysis? Why or why not? 2) Draw a millequivalent bar graph showing meq/L for a cation and anion balance. 3) What dose of lime and soda ash would be required to treat this water...
If a ground water contains H2S at concentration of 2 mg/L, determine the concentration of H2S...
If a ground water contains H2S at concentration of 2 mg/L, determine the concentration of H2S in head space of a closed tank containing the ground water at at 20 oC. Given that for H2S, Henry’s constant (H) is equal to 5.15×102 atm at 20 oC.
What is the concentration of Ca2+ in ppm (mg/L) in cave water saturated with calcite (calcium...
What is the concentration of Ca2+ in ppm (mg/L) in cave water saturated with calcite (calcium carbonate, Ksp = 4.7 × 10-9)? Answer:2.7
calcuate the concentration of dissolved oxygen (unit of mol/L and mg/L of water is equilibrated with...
calcuate the concentration of dissolved oxygen (unit of mol/L and mg/L of water is equilibrated with pure oxygen at 250C at 1.0 atm.
Water has total hardness of 155 mg/L as CaCO3 and contains 0.004 M HCO3- at pH...
Water has total hardness of 155 mg/L as CaCO3 and contains 0.004 M HCO3- at pH 7. What is the carbonate hardness and non-carbonate hardness in mg/L as CaCO3? Would you use lime softening or lime-soda softening for this water and why?
A groundwater supply has the following analysis: Ca2+ = 94 mg/l HCO3- = 317 mg/l Mg2+...
A groundwater supply has the following analysis: Ca2+ = 94 mg/l HCO3- = 317 mg/l Mg2+ = 24 mg/l SO42- = 67 mg/l Na+ = 14 mg/l C1- = 24 mg/l Calculate the quantities of lime and soda ash for excess-lime softening, and the carbon dioxide reacted for neutralization by two-stage recarbonation. Assume that the practical limits of hardness removal for calcium are 30 mg/1 as CaCO3 and for magnesium are 10 mg/1 as CaCO3 and that three-quarters of the...
Calculate the hardness using the following concentrations: Na+=248mg/L K+=5.5mg/L Ca2+=54mg/L Mg2+=26mg/L
Calculate the hardness using the following concentrations: Na+=248mg/L K+=5.5mg/L Ca2+=54mg/L Mg2+=26mg/L
Assume that a chemical of concern has a concentration of 12 mg/L in drinking water. Determine...
Assume that a chemical of concern has a concentration of 12 mg/L in drinking water. Determine the dose of the chemical for adults and children. What is the cancer risk associated with this exposure if the slope factor is determined to be 0.065 (mg/kg-d)-1 for oral exposure? If 10,000 individual consumed this water over their lifetime what number would likely get cancer?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT