Other Solution Concepts - AP Chemistry

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:

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.

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.

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,

Since is a strong acid, calculations should be carried out assuming that the compound dissociates completely:

and are produced in a 1:1 ratio to total dissolved , so the concentration of in solution is the same as the concentration of :

pH is related to the concentration of :

For a solution of known volume and concentration (molarity in this case), the volume needed to dilute the solution to a desired concentration may be found using the formula:

Where and are the initial and final concentrations, and and are the initial and final volumes. So, for 750mL (0.750L) of a 0.050M solution diluted to 0.015M:

Solving for :

Now that we know the total volume needed, we may find the volume that must be added by subtracting the initial volume () from the final volume ():

1.75L of water must be added to 750mL of 0.050M in order to achieve a final concentration of 0.015M

Osmotic pressure is represented by:

Where Van’t hoff factor, , gas constant , temperature in . The Van’t hoff factor is a unitless number that represents the amount of ionic species that the compound will dissociate in solution. is part of a large group of molecules classified as hydrocarbons which normally do not dissociate at all in solution. Therefore, .

Plug in known values and solve.

In order to calculate the concentration, we must use molarity formula:

We must use the molecular weight of to calculate the moles of solute:

In order to calculate the concentration, we must use molarity formula:

We must use the molecular weight of to calculate the moles of solute:

In order to calculate the number of milliliters, we must first determine the number of moles in 5 grams of using its molecular weight as a conversion factor:

Using the concentration units as a conversion factor and the number of moles calculated, the number of milliliters can be calculated:

Use the dilution formula:

Rearranging this equation gives:

Plugging in the values gives:

Therefore, after diluting the solution to 20mL, the solution concentration would be lowered from 0.50M to 0.25M.

Solutes that dissociate completely in a solution are called strong electrolytes. Weak electrolytes stay paired to some extent in solutions. As a result, strong electrolytes include ionic compounds and strong acid and bases.

Solubility product, , is the product of ion concentrations at equilibrium in a saturated solution of salt. All other definitions are true.

In order to calculate the number of milliliters, we must first determine the number of moles in 5 grams of using its molecular weight as a conversion factor:

Using the concentration units as a conversion factor and the number of moles calculated, the number of milliliters can be calculated:

1.075 g / mL * 0.475 L

First, convert to mL

1.075 g / mL * 475 mL = 510.6 g

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:

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.

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.

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,