To determine the mass of a solute (the dissolved substance) in a solution, you can use a straightforward formula that relates the solution's volume to its concentration. This method is particularly useful when dealing with solutions where the concentration is expressed in grams per liter (g/L).
Understanding the Formula
The mass of a substance dissolved in a liquid can be calculated by multiplying the volume of the liquid by its concentration. This foundational principle allows for precise measurement of the solute's quantity.
The formula for calculating the mass of a solute is:
Mass of Solute (grams) = Volume of Solution (litres) × Concentration of Solution (g/L)
Key Components Explained
Understanding each variable in the formula is crucial for accurate calculations:
- Mass of Solute (grams): This is the quantity you are seeking to find. It represents the total mass of the specific substance that has been dissolved in the solvent to form the solution.
- Volume of Solution (litres): This refers to the total volume occupied by the liquid solution. It is essential that this value is in litres for the formula to yield the correct result. If you have the volume in milliliters (mL), convert it to litres by dividing by 1000 (since 1 L = 1000 mL).
- Concentration of Solution (g/L): This metric indicates the amount of solute, in grams, present in each litre of the solution. It quantifies the strength or density of the solute within the solution.
Practical Application and Example
Applying this formula is a simple process once you have the necessary values for the solution's volume and concentration.
Example Scenario: Calculating Mass of NaCl
Imagine you have 500 mL of a sodium chloride (NaCl) solution with a known concentration of 25 g/L. To find the mass of NaCl dissolved in this particular solution, follow these steps:
-
Convert Volume to Litres:
Since the volume is given in milliliters, convert it to litres:
500 mL ÷ 1000 mL/L = 0.5 L -
Apply the Formula:
Substitute the converted volume and the given concentration into the formula:
Mass of NaCl (grams) = 0.5 L × 25 g/L -
Calculate the Mass:
Perform the multiplication to find the mass of the solute:
Mass of NaCl = 12.5 grams
This calculation reveals that there are 12.5 grams of sodium chloride dissolved in the 500 mL solution.
Summary of Example Data
The following table summarizes the values used in the example calculation:
| Component | Value in Example | Unit |
|---|---|---|
| Volume of Solution | 0.5 | Litres |
| Concentration | 25 | g/L |
| Calculated Mass of Solute | 12.5 | grams |
By utilizing the simple relationship between volume, concentration, and mass, you can precisely determine the amount of a solute present in a given solution.
