Calculate the mass of EDTA (molar mass = 372.24 g/mol) to prepare 500 mL of an approximately 0.01 M EDTA solution. [show steps]
The correct answer and explanation is:
To calculate the mass of EDTA required to prepare 500 mL of a 0.01 M EDTA solution, follow these steps:
Step 1: Convert volume to liters
The volume of the solution is 500 mL, but the molarity (M) is expressed in moles per liter. To convert milliliters to liters: 500 mL=0.500 L500 \, \text{mL} = 0.500 \, \text{L}
Step 2: Use the molarity formula
The molarity formula is: M=moles of solutevolume of solution in litersM = \frac{\text{moles of solute}}{\text{volume of solution in liters}}
Rearrange this formula to solve for the moles of solute (EDTA): moles of EDTA=M×V\text{moles of EDTA} = M \times V
Where:
- M=0.01 MM = 0.01 \, \text{M} (molarity of EDTA)
- V=0.500 LV = 0.500 \, \text{L} (volume of solution in liters)
Now calculate the moles of EDTA: moles of EDTA=0.01 mol/L×0.500 L=0.005 mol\text{moles of EDTA} = 0.01 \, \text{mol/L} \times 0.500 \, \text{L} = 0.005 \, \text{mol}
Step 3: Convert moles to mass
To find the mass of EDTA, use the relationship: mass=moles×molar mass\text{mass} = \text{moles} \times \text{molar mass}
The molar mass of EDTA is 372.24 g/mol. Now calculate the mass: mass=0.005 mol×372.24 g/mol=1.8612 g\text{mass} = 0.005 \, \text{mol} \times 372.24 \, \text{g/mol} = 1.8612 \, \text{g}
Step 4: Final Answer
The mass of EDTA required to prepare 500 mL of a 0.01 M solution is 1.8612 g.
Explanation:
To prepare a specific molarity solution, first convert the volume to liters since molarity is moles per liter. Then use the molarity formula to calculate how many moles of EDTA are needed for the desired concentration and volume. Finally, multiply the number of moles by the molar mass of EDTA to determine the mass needed. This method ensures that the correct amount of substance is used for the solution preparation.