Question #76da3
1 Answer
Explanation:
The first thing to do here is to figure out how much potassium nitrate you can dissolve in water at
You already know that at
In other words, you get
#"155 g KNO"_3 + "100.0 g H"_2"O" = "255 g solution"#
You can now use this as a conversion factor to figure out how much potassium nitrate you get in
#550.0 color(red)(cancel(color(black)("g solution"))) * "155 g KNO"_3/(255color(red)(cancel(color(black)("g solution")))) = "334.3 g KNO"_3#
You can now say that at
#"550.0 g solution " - " 334.3 g KNO"_3 = "215.7 g H"_2"O"#
Now, when you cool the solution to
You know that this solution contains
#215.7 color(red)(cancel(color(black)("g H"_2"O"))) * "38.0 g KNO"_3/(100.0color(red)(cancel(color(black)("g H"_2"O")))) = "81.97 g KNO"_3#
This means that your solution can hold a maximum of
#m_"crystallize" = "334.3 g" - "81.97 g"#
#m_"crystallize" = "252.3 g KNO"_3#
Rounded to three sig figs, the answer will be
#m_"crustallize" = color(darkgreen)(ul(color(black)("252 g KNO"_3)))#
Therefore, you can say that
The difference between these two values will crystallize out of solution as a result of the decrease in solubility associated with the decrease in temperature.