Math Problem Statement

What is the molar concentration of a 100 mL aqueous solution that contains 2.00 g KCl (molar mass = 74.55 g/mol)?

Solution

To find the molar concentration of the KCl solution, we can follow these steps:

  1. Calculate the number of moles of KCl:

Moles of KCl=Mass of KCl (g)Molar mass of KCl (g/mol)\text{Moles of KCl} = \frac{\text{Mass of KCl (g)}}{\text{Molar mass of KCl (g/mol)}}

Given:

  • Mass of KCl = 2.00 g
  • Molar mass of KCl = 74.55 g/mol

Moles of KCl=2.00g74.55g/mol=0.02684mol\text{Moles of KCl} = \frac{2.00 \, \text{g}}{74.55 \, \text{g/mol}} = 0.02684 \, \text{mol}

  1. Convert the volume of the solution from mL to L:

Since molarity is defined as moles per liter, we need to convert 100 mL to liters:

100mL=0.100L100 \, \text{mL} = 0.100 \, \text{L}

  1. Calculate the molar concentration (Molarity):

Molarity=Moles of KClVolume of solution (L)\text{Molarity} = \frac{\text{Moles of KCl}}{\text{Volume of solution (L)}}

Molarity=0.02684mol0.100L=0.2684mol/L\text{Molarity} = \frac{0.02684 \, \text{mol}}{0.100 \, \text{L}} = 0.2684 \, \text{mol/L}

So, the molar concentration of the KCl solution is 0.268 M.

Would you like further details or have any questions?

Here are some related questions for further exploration:

  1. How would the concentration change if the volume of the solution were doubled?
  2. What would be the concentration if 5.00 g of KCl were dissolved in the same 100 mL?
  3. How would the molarity differ if you used NaCl instead of KCl with the same mass?
  4. What would be the concentration in ppm (parts per million) for this solution?
  5. How can the dilution equation M1V1=M2V2M_1V_1 = M_2V_2 help in creating solutions of lower concentrations?

Tip: Always ensure your solution volume is converted to liters when calculating molarity.

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Math Problem Analysis

Mathematical Concepts

Molarity
Stoichiometry
Unit Conversion

Formulas

Moles of KCl = Mass of KCl (g) / Molar mass of KCl (g/mol)
Molarity = Moles of solute / Volume of solution (L)

Theorems

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Suitable Grade Level

Grades 10-12