25.0 mL tap water is titrated with 0.00500 M EDTA 7.95mL EDTA is required for complete reaction with water hardness what is the molarity of the total water hardness
mols = M x L = 0.00500 x 0.00795 = ?
M = mols/L soln (25 mL = 0.025L)
To determine the molarity of the total water hardness, we need to use the information provided about the titration.
Step 1: Identify the balanced chemical equation:
In this case, since EDTA is used to titrate the water hardness, the balanced chemical equation is:
EDTA + Metal ion → Metal-EDTA complex
Step 2: Determine the mole ratio between EDTA and the metal ion:
Based on the balanced chemical equation, the mole ratio between EDTA and the metal ion is 1:1. That means, for every 1 mole of metal ion, we will require 1 mole of EDTA.
Step 3: Convert the given volume of EDTA solution to moles:
Given that 7.95 mL of 0.00500 M EDTA solution is required for complete reaction with the water, we can calculate the moles of EDTA used:
Moles of EDTA = volume of EDTA solution (L) x molarity of EDTA solution (mol/L)
Moles of EDTA = 0.00795 L x 0.00500 mol/L
Step 4: Determine the moles of the metal ion:
Since the mole ratio between EDTA and the metal ion is 1:1, the moles of EDTA used will be equal to the moles of metal ion present in the water.
Step 5: Calculate the molarity of the total water hardness:
We know that 25.0 mL of tap water is titrated. To calculate the molarity of the total water hardness, we need to convert the volume of water to liters and then divide the moles of the metal ion by the volume of water in liters:
Molarity of total water hardness (M) = moles of metal ion / volume of water (L)
Now, let's perform the calculations:
Step 3: Moles of EDTA = 0.00795 L x 0.00500 mol/L = 0.00003975 mol EDTA
Step 4: Moles of metal ion = 0.00003975 mol
Step 5: Molarity of total water hardness = 0.00003975 mol / 0.0250 L = 0.00159 M
Therefore, the molarity of the total water hardness is 0.00159 M.