Here is a following practice question on my study guide. i have no idea on how to do it. Any help would be appreciated! Thanks you.
A solution contains 26.5g NaCl in 75.0g H2O at 20 degrees Celsius. Determine if the solution is saturated, unsaturated, or supersaturated. (The solubility of NaCl at 20 Degrees is 36.0g/100g H2O) Show work.
Thank you!
But how would i figure out the "??"
I totally suck at chemistry!.. idk how to find the solubility ..?
There is no chemistry in the problem. It's all math and not very advanced math at that.
How do you figure out the ?? in the equation:
36.0 x (75.0 g H2O/100 g H2O) = ??
You key in 36.0 on your calculator, multiply by 75.0 and divide by 100. That's all there is to it.
To determine if a solution is saturated, unsaturated, or supersaturated, you need to compare the actual amount of solute (NaCl) in the solution to the maximum amount of solute that can be dissolved at the given temperature and pressure. In this case, you have the actual amount of NaCl (26.5g) and the solubility of NaCl at 20 degrees Celsius (36.0g/100g H2O).
First, calculate the amount of water in the solution by subtracting the mass of NaCl from the total mass of the solution:
Mass of water = Total mass of solution - Mass of NaCl
Mass of water = 75.0g H2O - 26.5g NaCl
Next, you need to calculate the maximum amount of NaCl that can be dissolved in the given amount of water at 20 degrees Celsius. Use the solubility information provided:
Maximum amount of NaCl = solubility of NaCl x Mass of water
Substitute the values into the equation:
Maximum amount of NaCl = 36.0g/100g H2O x (75.0g H2O - 26.5g NaCl)
Now, calculate the maximum amount of NaCl that can be dissolved:
Maximum amount of NaCl = (36.0g/100g) x (75.0g - 26.5g)
Maximum amount of NaCl = (36.0/100) x (75.0 - 26.5)g
Maximum amount of NaCl = 0.36 x 48.5g
Maximum amount of NaCl = 17.46g
Finally, compare the actual amount of NaCl (26.5g) to the maximum amount of NaCl that can be dissolved (17.46g).
If the actual amount is less than the maximum amount, the solution is unsaturated.
If the actual amount is equal to the maximum amount, the solution is saturated.
If the actual amount is greater than the maximum amount, the solution is supersaturated.
In this case, since 26.5g is greater than 17.46g, the solution is supersaturated.
The question is telling you that the solubility is 36 g NaCl/100 g H2O and it is asking what the solubility is in 75 g H2O. Just set up a proportion OR use dimensional analysis.
36.0 g x (75.0 g H2O)/100 g H2O) = ??
Then compare that number of ?? with 26.5 and you will know which of the it is. If you want a ratio/proportion, it would be set up like this:
36/100 = ??/75