MCAT Physical › Solubility and Ions
Which of the following will not increase the solubility of a solution?
Increasing the temperature of a gas solute in a liquid solvent
Increasing the temperature of a solid solute in a liquid solvent
Increasing the pressure of a gas solute in a liquid solvent
Decreasing the temperature of a gas solute in a liquid solvent
All of these will increase solubility
Increasing the temperature of a gas solute in a liquid solvent will decrease solubility. While dissolved, the gas is in equilibrium with the liquid. Adding heat will push the equilibrium in favor of the gas, causing it to precipitate from solution in the form of bubbles.
Increasing the pressure of a gas solute in a liquid solvent, decreasing the temperature of a gas solute in a liquid solvent, and increasing the temperature of a solid solute in a liquid solvent will all increase the solubility.
Which of the following will not increase the solubility of a solution?
Increasing the temperature of a gas solute in a liquid solvent
Increasing the temperature of a solid solute in a liquid solvent
Increasing the pressure of a gas solute in a liquid solvent
Decreasing the temperature of a gas solute in a liquid solvent
All of these will increase solubility
Increasing the temperature of a gas solute in a liquid solvent will decrease solubility. While dissolved, the gas is in equilibrium with the liquid. Adding heat will push the equilibrium in favor of the gas, causing it to precipitate from solution in the form of bubbles.
Increasing the pressure of a gas solute in a liquid solvent, decreasing the temperature of a gas solute in a liquid solvent, and increasing the temperature of a solid solute in a liquid solvent will all increase the solubility.
The solubility product constant of is
. What is the solubility of this compound?
Solubility is the ability of a solute to dissolve into a solvent. It is calculated by creating an equilibrium equation and solving for the concentration of dissolved ions.
For this question, we will need to set up the equilibrium constant equation for calcium hydroxide.
Note that the solid compound is not included in the equilibrium expression. Now we can work on finding the solubility. For each mole of calcium hydroxide dissolved, one mole of calcium ions and two moles of hydroxide ions are released. Mathematically, we can equate this ratio to the ion concentrations in the equilibrium calculation.
In this calculation, is the solubility. Given the solubility constant, we can solve for
.
The solubility product constant of is
. What is the solubility of this compound?
Solubility is the ability of a solute to dissolve into a solvent. It is calculated by creating an equilibrium equation and solving for the concentration of dissolved ions.
For this question, we will need to set up the equilibrium constant equation for calcium hydroxide.
Note that the solid compound is not included in the equilibrium expression. Now we can work on finding the solubility. For each mole of calcium hydroxide dissolved, one mole of calcium ions and two moles of hydroxide ions are released. Mathematically, we can equate this ratio to the ion concentrations in the equilibrium calculation.
In this calculation, is the solubility. Given the solubility constant, we can solve for
.
What is the molarity of a 1L solution composed of water and 300g of sodium iodide?
2M
1M
0.5M
4M
Sodium iodide is given by the formula NaI, and has a molecular weight of 150g/mol. Molarity is found by dividing the moles of solute by liters of solvent.
We find the moles of sodium iodide by using the mass (300g) and molecular weight.
We know our volume is 1L, so now we can solve for the molarity.
What is the molarity of a 1L solution composed of water and 300g of sodium iodide?
2M
1M
0.5M
4M
Sodium iodide is given by the formula NaI, and has a molecular weight of 150g/mol. Molarity is found by dividing the moles of solute by liters of solvent.
We find the moles of sodium iodide by using the mass (300g) and molecular weight.
We know our volume is 1L, so now we can solve for the molarity.
A chemist has 300mL of a 0.75M solution and needs to dilute it to 0.35M. How much solvent should be added?
Use the equation for molarity, , first to figure out the number of moles of solute present.
Solving this gives 0.225 moles of solute. Using the same equation again with the final molarity will give the final volume.
Finally, the amount of solvent added is the difference between initial and final total volumes.
0.643L – 0.300L = 0.342L added
What is the molality of a solution when 300mmol of HBr is added to 60g of ether?
Molality is the number of moles of solute divided by kilograms of solvent. Because we are given the solute in mmol and the solvent in grams, we must convert them to moles and kilograms, respectively.
300 mmol is 0.3 moles. Additionally 60 grams is 6 x 10-2 kg.
Now we can solve for the molality.
A chemist has 300mL of a 0.75M solution and needs to dilute it to 0.35M. How much solvent should be added?
Use the equation for molarity, , first to figure out the number of moles of solute present.
Solving this gives 0.225 moles of solute. Using the same equation again with the final molarity will give the final volume.
Finally, the amount of solvent added is the difference between initial and final total volumes.
0.643L – 0.300L = 0.342L added
What is the molality of a solution when 300mmol of HBr is added to 60g of ether?
Molality is the number of moles of solute divided by kilograms of solvent. Because we are given the solute in mmol and the solvent in grams, we must convert them to moles and kilograms, respectively.
300 mmol is 0.3 moles. Additionally 60 grams is 6 x 10-2 kg.
Now we can solve for the molality.