What is the original amount of solid that was dissolved if 213.0 mL of solvent resulted in 21.0% of the solubility remains?

To determine the original amount of solid that was dissolved, we first need to understand the implications of the given percentage of solubility that remains after dissolving the solid in the solvent. The fact that 21.0% of solubility remains indicates that 79.0% of the solid has already dissolved.

Since we know the volume of the solvent is 213.0 mL, we can infer that the solubility of the solid in this volume has reached a particular concentration. Solubility is typically expressed in grams of solute per 100 mL of solvent or in similar units.

The percentage remaining (21.0%) denotes that this is the amount that has not yet dissolved. To find the original mass of the solid that was dissolved, we need to calculate the total mass of solid corresponding to the percentage dissolved, which can be determined from the relationship:

Total mass of solid original = Mass dissolved + Mass remaining.

Let’s go through the calculations. If 21% of the solid remains undissolved, then 79% has been dissolved. If we assume x grams is the original amount of solid, we can express this mathematically as:

0.79x (dissolved) + 0