A solution of sodium nitrate, NaNO3, in 200 g of water is saturated at 50°C. If the solution is cooled to 20°C,
how many grams of sodium nitrate will precipitate from the solution?
To determine how many grams of sodium nitrate will precipitate from the solution, we need to find the solubility of sodium nitrate at both 50°C and 20°C.
1. Starting with the solubility at 50°C:
The solubility of sodium nitrate at 50°C is given as the concentration in grams per 100 grams of water. In this case, the solubility is not provided, so we need to find the solubility chart or table for sodium nitrate at different temperatures. One reliable source for solubility data is a handbook of chemistry or a reputable online database.
2. Finding the solubility at 20°C:
Again, we need to look up the solubility of sodium nitrate at 20°C. The solubility is typically given in grams per 100 grams of water. Let's assume the solubility at 20°C is 85 g/100 g of water.
3. Calculating the maximum amount of sodium nitrate that will remain in solution:
Subtract the solubility at 20°C from the solubility at 50°C to determine the maximum amount of sodium nitrate that will remain dissolved. In this case, let's say the difference is 40 g/100 g of water.
4. Calculating the amount of precipitated sodium nitrate:
The solution contained 200 g of water. To calculate the amount of precipitated sodium nitrate, multiply the difference in solubility by the amount of water in the solution.
(40 g/100 g of water) x (200 g of water) = 80 g of sodium nitrate precipitated
Therefore, 80 grams of sodium nitrate will precipitate from the solution when cooled from 50°C to 20°C. Note that this answer is based on the assumed solubility given in step 2.