All AP Chemistry Resources
Example Questions
Example Question #1 : Solubility And Equilibrium
Calculate the molar solubility of AgBr in 0.050 M AgNO3 at room temperature. The Ksp of AgBr is 5.4 x 10-13.
1.08 M
2.16 M
1.08 x 10-11 M
1.57 x 10-12 M
2.16 x 10-11 M
1.08 x 10-11 M
Example Question #1 : Solubility And Equilibrium
Would the molar solubility of Cr(OH)3 increase or decrease as the pH is lowered (i.e. made more acidic)?
Increase
There is no change
Decrease
Can not be determined
Increase
Since Cr(OH)3 is a basic salt, decreasing the pH makes it more soluble.
Example Question #1 : Solubility And Equilibrium
Calculate the molar solubility of SrF2 in 0.023M NaF. The Ksp for SrF2 is 4.3 x 10-9.
3.2 x 10-5 M
8.1 x 10-6 M
5.2 x 10-4 M
1.6 x 10-3 M
3.2 x 10-3 M
8.1 x 10-6 M
Example Question #41 : Solutions
Calculate the molar solubility of Mn(OH)2 at pH 9.5. The Ksp for Mn(OH)2 is 1.6 x 10-13.
2.1 x 10-5 M
1.5 x 10-3 M
1.6 x 10-4 M
2.4 x 10-3 M
3.5 x 10-4 M
1.6 x 10-4 M
Example Question #42 : Solutions
Calculate the molar solubility of CaF2 (Ksp = 3.9 x 10-11) in a room temperature solution of 0.010 M Ca(C2H3O2)2.
1.6 x 10-2 M
3.2 x 10-2 M
3.1 x 10-5 M
4.2 x 10-4M
3.7 x 10-4 M
3.1 x 10-5 M
Example Question #1 : Other Solution Concepts
A solution on NaCl has a denisty of 1.075 g/mL. If there are 0.475 L of solution present, what is the mass?
1.075 g / mL * 0.475 L
First, convert to mL
1.075 g / mL * 475 mL = 510.6 g
Example Question #43 : Solutions
5L of 0.1M NaCl and 10L of 0.2M NaI are combined in a single vessel.
What is the final concentration of sodium ions in solution?
NaCl and NaI are both highly soluble; thus both solutions can be treated as containing separate ions of sodium, chloride, and iodide.The final concentration can be found by finding the total number of moles of sodium ions and the total volume from both solutions.
We can find the moles of sodium ions from each solution by multiplying the volume by the molar concentration.
The total moles of sodium ions is:
Divide this by the total solution volume to find the final concentration:
Example Question #1 : Other Solution Concepts
Given that the pKa of acetic acid is 4.76, what is the percentage of the protonated form of acetic acid in a solution where the pH is 6?
There is not enough information given
In order to solve this problem, we first must use the Henderson-Hasselbalch equation:
Since we are given the pH of the solution and the pKa of acetic acid, we are able to solve for the ratio of conjugate base to acid:
Now that we have the ratio of conjugate base to acid, we need to calculate the percentage of the acid, or protonated form, in solution. To do this, it's important to realize that for every 17.38 moles of conjugate base, there is 1 mol of acid. Therefore, the total amount of acetic acid + acetate is equal to 18.38.
Example Question #4 : Other Solution Concepts
Suppose that two containers, and , contain equal amounts of water. If 5 moles of is added to solution and 5 moles of glucose is added to solution , which solution will experience a greater increase in boiling point?
There is not enough information to answer the question
Solution , because is able to dissociate into and ions, thus resulting in a greater amount of particles dissolved in solution
Solution , because glucose has a greater molar mass than
Neither solution will experience a change in boiling point
Both solutions will exhibit the same change in boiling point
Solution , because is able to dissociate into and ions, thus resulting in a greater amount of particles dissolved in solution
In the question stem, we are told that equal molar amounts of and glucose are added to containers and , respectively. The change in boiling point of water is a colligative property that is dependent on the number of dissolved solute particles, regardless of their identity. The addition of 5 moles of will result in approximately 10 moles of dissolved solute, since each mol of can dissociate into two ions, according to the following reaction:
Glucose, on the other hand, does not dissociate and simply remains as intact molecules. Thus, the addition of 5 moles of glucose to container results in 5 moles of dissolved solute. Since solution contains approximately twice as many dissolved solute particles as does solution , it will experience a greater increase in the boiling point of water.
Example Question #51 : Solutions
Approximately what is the pH of a solution of at ?
There is insufficient information to answer the question
We are given the concentration of in solution and asked to find the pH. To do this, we must make use of the following equation:
It is also important to realize that is a strong base and will thus dissociate completey according to the following reaction:
Thus, for every one mol of that reacts, an equal number of moles of will be produced. And since there are to begin with, then will be produced.
Remember that this calculated value so far is the pOH, not the pH! To calculate the pH, it is vital to remember that at . Thus,
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