A scientist has a solution containing 250 ml of 0.5 M HCl. She dilutes it with water to make a total volume of 1 liter. What is the new molarity of the solution?
["Title: How to Calculate New Molarity After Dilution: A Practical Example with HCl", "When working with chemical solutions in laboratories, dilution is a frequently performed technique that scientists use to adjust concentrations safely. In this article, we explore a clear and practical example involving hydrochloric acid (HCl) to illustrate how to calculate the new molarity after dilution.", "---", "### The Problem", "A scientist begins with 250 mL (0.25 L) of a 0.5 M (molar) hydrochloric acid (HCl) solution. She dilutes this by adding water until the total volume reaches 1 liter (1.0 L). What is the new molarity of the diluted HCl solution?", "---", "### Step 1: Understand the Concept of Molarity", "Molarity (M) is defined as the number of moles of solute per liter of solution:", "[\n\ ext{Molarity} = \frac{\ ext{moles of solute}}{\ ext{volume of solution in liters}}\n]", "The key point is that dilution maintains the total amount of solute — only the concentration per unit volume changes.", "---", "### Step 2: Calculate the Initial Moles of HCl", "First, calculate the moles of HCl in the original solution:", "[\n\ ext{Moles of HCl} = \ ext{Molarity} \ imes \ ext{Volume (in L)} = 0.5, \ ext{mol/L} \ imes 0.25, \ ext{L} = 0.125, \ ext{mol}\n]", "---", "### Step 3: Determine the Final Volume After Dilution", "The scientist adds water until the total volume is 1 liter (1000 mL):", "[\n\ ext{Final Volume} = 1.0, \ ext{L}\n]", "---", "### Step 4: Calculate the New Molarity", "Using the same moles of HCl (since dilution doesn’t destroy solute), the new molarity is:", "[\n\ ext{New Molarity} = \frac{\ ext{moles of HCl}}{\ ext{final volume in liters}} = \frac{0.125, \ ext{mol}}{1.0, \ ext{L}} = 0.125, \ ext{M}\n]", "---", "### Conclusion", "By applying the dilution formula:", "[\nM_1 V_1 = M_2 V_2\n]", "Or simply calculating total moles and dividing by final volume, the scientist’s 0.5 M HCl solution diluted to 1.0 L results in a new molarity of 0.125 M.", "This method is essential in chemistry for ensuring accurate concentration control in experiments and industrial applications.", "---", "Keywords: HCl molarity, dilution calculation, molarity dilutions, chemistry lab techniques, solution concentration, chemical concentration formula, moles to molarity conversion."]
