how many grams of solute will be left if a saturated solution of NaNO3 in 50 grams of water at 30 degrees celsius is completely evaporated to dryness?
The Correct Answer and Explanation is :
To solve this, we need to determine how many grams of NaNO₃ (sodium nitrate) will remain in the solution after the water has evaporated. This can be done by first finding the solubility of NaNO₃ in water at 30°C, and then applying that information to the 50 grams of water in the solution.
Step 1: Find the solubility of NaNO₃ at 30°C
The solubility of NaNO₃ in water at 30°C is approximately 92 grams of NaNO₃ per 100 grams of water.
Step 2: Determine how much NaNO₃ can dissolve in 50 grams of water
Since the solubility is 92 grams per 100 grams of water, we can set up a proportion to find how many grams of NaNO₃ can dissolve in 50 grams of water:
[
\frac{92 \text{ g NaNO₃}}{100 \text{ g H₂O}} = \frac{x \text{ g NaNO₃}}{50 \text{ g H₂O}}
]
Solving for (x):
[
x = \frac{92 \times 50}{100} = 46 \text{ g NaNO₃}
]
Step 3: Evaporation process
When the water is completely evaporated, the dissolved NaNO₃ will be left behind as solid crystals. Since the solubility at 30°C is 46 grams of NaNO₃ in 50 grams of water, and the solution is saturated, all 46 grams of NaNO₃ will remain after the evaporation process.
Final Answer:
After the solution is evaporated to dryness, 46 grams of NaNO₃ will remain as the solute.
Explanation:
Solubility refers to the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature. At 30°C, 92 grams of NaNO₃ can dissolve in 100 grams of water, meaning a saturated solution at that temperature would contain this maximum amount of solute. Since the solution is saturated, we know that 46 grams of NaNO₃ will dissolve in 50 grams of water. Upon evaporation, all 46 grams of NaNO₃ will be left behind as the water (solvent) evaporates completely, leaving the solute behind as solid NaNO₃.