The molarity of a 0.50 liter aqueous solution containing 0.20 mole of NaOH is 0.4 M.
Understanding Molarity
Molarity ($M$) is a fundamental concept in chemistry used to express the concentration of a solution. It is defined as the number of moles of solute dissolved per liter of solution. This unit is particularly useful for stoichiometric calculations in chemical reactions.
The formula for molarity is:
$$ \text{Molarity (M)} = \frac{\text{Moles of Solute}}{\text{Liters of Solution}} $$
Where:
- Moles of Solute refers to the amount of the substance dissolved.
- Liters of Solution refers to the total volume of the solution, including both the solute and the solvent.
Molarity is typically expressed in units of moles per liter (mol/L) or simply "M".
Calculating the Molarity of the NaOH Solution
To determine the molarity of the given sodium hydroxide (NaOH) solution, we use the provided information:
- Moles of NaOH (solute): 0.20 mole
- Volume of solution: 0.50 liters
Step-by-Step Calculation
-
Identify the given values:
- Moles of NaOH = 0.20 mol
- Volume of solution = 0.50 L
-
Apply the molarity formula:
$$ M = \frac{\text{Moles of Solute}}{\text{Liters of Solution}} $$
$$ M = \frac{0.20 \text{ mol}}{0.50 \text{ L}} $$ -
Perform the division:
$$ M = 0.4 \text{ mol/L} $$
Therefore, the molarity of the solution is 0.4 M.
Summary of Data
The following table summarizes the values used in the calculation:
| Component | Value | Unit |
|---|---|---|
| Moles of Solute | 0.20 | mole |
| Volume of Solution | 0.50 | liter |
| Molarity | 0.4 | M |
Why Molarity Matters
Molarity is a crucial concentration unit in various scientific and practical applications, including:
- Chemical Reactions: It allows chemists to precisely measure the amount of reactants needed for a reaction or determine the concentration of products.
- Laboratory Work: In laboratories, solutions of specific molarities are routinely prepared for experiments, titrations, and analytical procedures.
- Pharmaceuticals: Accurate concentration measurements are vital in drug formulation to ensure correct dosages.
- Environmental Science: Molarity is used to quantify pollutants in water samples or the concentration of nutrients in ecosystems.
Understanding how to calculate and apply molarity is fundamental for anyone working with chemical solutions. For more detailed information on molarity and related concepts, you can explore resources like Wikipedia's article on Molar Concentration or chemistry textbooks.
