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Dilution is the process of lowering the concentration of a solute in a solution by varying the amount of solvent present. The definition of a dilute solution necessitates a basic understanding of mixture chemistry. Dilution chemistry is essential for performing chemical reactions, manufacturing, biomedical research, and other tasks. Solutions can even be found in our daily lives. One good example is the saltwater solution in which the solute is salt and the solvent is water.
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Key Takeaways: Dilution formula, Dilution, Solution, Solvent, Mass percent, Mole fraction, Molarity
Dilution Formula
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A dilution formula is available to assist scientists in calculating the appropriate amount of solvent to dilute a solution. The dilution formula takes into account the starting and ending solute concentrations in molarity, or moles per liter solution, as well as the total volume of the solution in liters. The formula is as follows:
M1V1 = M2V2
Where,
- M1 is the starting solution's molarity
- V1 is the starting solution's volume
- M2 denotes the molarity of the final solution
- V2 denotes the volume of the final solution.
Dilution Equation and Dilution Calculation
The dilution formula can be used to generate equations for determining how to dilute a solution. Assume a chemist wishes to make 1 L of 2 M glucose solution from a 4 M glucose solution. How much of the first solution would they require? To begin, we can rearrange the above-mentioned dilution equation.
M1V1 = M2V2
V1 = M2 V2 / M1
V1 = 2 M * 1 L / 4 M
V1 = 0.5 L
V1 is equal to 0.5 L.
As a result, we know the final volume is 1 L and that 0.5 L of the original was used. As a result, we can subtract the volume of the original solution from the volume of the final solution:
1 L - 0.5 L = 0.5 L added solvent
To finish the dilution, combine 0.5 L of the original solution and 0.5 L of solvent.
Dilution Factor Calculation
What exactly is the dilution factor? A dilution factor is a factor that is used to dilute the original solution or stock solution. You may be wondering how to calculate the dilution factors for any solution. The dilution factor equation can be used to calculate the dilution factor. The formula is as follows:
V2 / V1 = M1 / M2
We can use the above problem to figure out the dilution factor for that solution. The concentration of the starting solution was 4M, and the concentration of the ending solution was 2M.
4 M / 2 M = 2
As a result, the dilution factor in the preceding example was 2.
Things to Remember
- The process of lowering the concentration of a given solute in its solution is known as dilution. The chemist can simply add more solvent to the mixture. Dilution also refers to a decrease in the pH of a chemical, which can be a gas, vapour, or solution.
- Mathematically, the volume of solvent required to prepare the desired concentration of a new, diluted solution can be calculated. The following is the relationship: M1V1 = M2V2
- M1 represents the original solution's concentration, and V1 represents the original solution's volume; M2 represents the diluted solution's concentration, and V2 represents the diluted solution's final volume. When calculating dilution factors, it is critical to use the same units for volume and concentration on both sides of the equation.
- The concentration of a solution is measured in terms of mass percent, mole fraction, molarity, molality, and normality. It is critical to keep the units of volume and concentration consistent when calculating dilution factors.
Also Read: Concentration of a Solution: Percentage, Molarity, Mole Fraction
Sample Questions
Ques: A nurse in a hospital must prepare an intravenous KCl dilution for a patient. The stock solution is 10% KCl, and the intravenous injection is 125 mL of 5% KCl. How much stock solution is required? (2 marks)
Ans: To begin, we employ our dilution equation.
M1V1 = M2V2
(10%) * V1 = 5% * 125 mL
V1 = 62.5 mL of 10% KCl
Because we need 125 mL total, we combine the following solvent with the 10% KCl:
125 mL - 62.5 mL = 62.5 mL of water
Ques: A scientist wishes to dilute 100 mL of a 5 M NaOH solution to make a new 1 L solution. What will the new solution's final concentration be? We also use the dilution equation to answer this question. (2 marks)
Ans: M1V1 = M2V2
5 M * 100 mL = M2 * 1000 mL
M2 = 0.5 M
Ques: A scientist wishes to dilute 100 mL of a 5 M NaOH solution to make a new 1 L solution. What will the new solution's final concentration be? We also use the dilution equation to answer this question. (3 marks)
Ans: Initial concentration of HCl is 6M
Final concentration of HCl is 1.5M
Final volume of solution is 5L
The initial volume needs to be found.
Substituting the values, we get
Vi = 1.5 x 5.0 / 6
= 1.3 L
Ques: What is the molarity of the diluted solution if 234 mL of a 2.51 molar aqueous solution is diluted with water to give a final solution volume of 356 mL? (2 marks)
Ans: M1V1 = M2V2
2.51*234= M2* 356
M2 = 1.65
Ques: To dilute a 1.75 M solution to 1.25 M, how much water must be added to 345 ml of the solution? (3 marks)
Ans: M1V1 = M2V2
1.75*345=1.25* V2
483ML = V2
The final volume of the second solution is 483 mL, but this does not answer the question. The difference between V1 and V2 is the volume of water that must be added.
A total of 483 – 345 = 138 mL of water must be added.
Ques: 175 ml of a 1.6 M aqueous solution of LiCi is diluted with water to a final volume of 1.0 L. What is the final concentration of the diluted solution? (2 marks)
Ans: M1V1 = M2V2
1.6*175= M2 *1000
M2 = 0.28
Ques: What is the final concentration of a 2.19 M solution diluted to 72.8 mL? (3 marks)
Ans: We can use the dilution equation to calculate
(2.19 M) (25.0 mL) = M2(72.8 mL)
Attempting to solve for the second concentration (noting that the millilitre units cancel),
M2 = 0.752 M.
The solution's concentration has decreased. To go from 25.0 mL to 72.8 mL, add 72.8 25.0 = 47.8 mL of solvent.
Ques: How much 5 M NaOH is required to make a 100 mL solution of 1 M NaOH? (3 marks)
Ans: Use the formula MiVi = MDVD.
Mi = 5 M
Vi = initial volume
MD = 1 M
VD = 100 mL
Solve for Vi
Vi = 20 Ml
Ques: How many mL of 0.25 M NaCl can you make from 300 mL of 1.5 M NaCl? (3 marks)
Ans: Use the formula MiVi = MDVD.
Mi = 1.5 M
Vi = 300 mL
MD = 0.25 M
VD = final volume
Solve for VD
VD = 1800 mL = 1.8 L
Ques: If you dilute 175 mL of a 1.6 M solution of LiCl to 1.0 L, determine the new concentration of the solution. (2 marks)
Ans: M1V1 = M2V2
(1.6 mol/L) (175 mL) = (x) (1000 mL)
x = 0.28 M
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