Based on the provided reference, the mass of solid dissolved in a solubility experiment is determined by subtracting the initial mass from the final mass.
The Core Calculation
To find the amount of solid that has dissolved, the method described involves a direct subtraction:
Mass of Solid Dissolved = Final Mass - Initial Mass
The reference explicitly states: "Calculate the mass of solid that dissolved by subtracting the initial mass from the final mass."
Understanding 'Initial' and 'Final' Mass in This Context
While various methods exist to measure dissolved mass, the calculation specified by the reference ("subtracting the initial mass from the final mass") suggests a particular experimental setup.
In this context, to yield a positive value representing the dissolved solid's mass, it is likely that:
- Initial Mass refers to the mass of the solvent (or the container plus the solvent) before any solid is added or dissolved.
- Final Mass refers to the mass of the solvent (or the container plus the solvent) after the solid has been added and dissolved, and any undissolved solid has been removed (e.g., by filtration).
The difference between these two masses would then equal the mass of the solid that successfully dissolved.
Experimental Procedure Steps (Based on Reference Context)
Following the context provided by the reference, a typical experimental approach incorporating this calculation would involve steps similar to these:
- Measure Initial Mass: Determine the mass of the solvent, perhaps within a container.
- Add Solid: Introduce a known amount of solid to the solvent.
- Allow Dissolution: Let the solid dissolve until saturation or equilibrium is reached.
- Separate Undissolved Solid: If some solid remains undissolved, it should be separated from the solution (e.g., by filtration or decantation).
- Measure Final Mass: Measure the mass of the solvent plus the dissolved solid remaining in the container.
- Calculate Dissolved Mass: Use the formula:
Final Mass - Initial Mass.
The reference also notes the importance of repeating the experiment for reliability:
- Repeat the Investigation: Conduct the experiment multiple times (e.g., twice more) using the same conditions.
- Calculate a Mean: Determine the average of the dissolved mass results from the repeated trials.
- Vary Temperature: Repeat the entire process at different temperatures to compare the solubility of the solid under varying conditions.
Calculation Summary
Here is a simple representation of the calculation based on the reference:
| Measurement | Description | Example (g) |
|---|---|---|
| Initial Mass | Mass of solvent (or container + solvent) | 100.0 |
| Final Mass | Mass of solvent + dissolved solid | 105.5 |
| Dissolved Mass | Final Mass - Initial Mass | 5.5 |
By following this calculation, as specified by the reference, you can determine the mass of solid that dissolved during the experiment.
