Concentration
We have described solutions in terms of the types of solvents and solutes; saturated, unsaturated or supersaturated; and electrolyte or non-electrolyte.
Solubility describes the maximum amount of solute that can dissolve in a certain amount of solvent. In this lesson we will look at solutions that may not be saturated.
Solubility describes the maximum amount of solute that can dissolve in a certain amount of solvent. In this lesson we will look at solutions that may not be saturated.
Concentration is defined as the amount of a particular substance in a given amount of another substance,
especially a solution or mixture. (ie. the amount of solute in a given amount of solvent).
If you look at the label of a juice container, you will probably see the words "juice from concentrate" or "frozen concentrated orange juice". This is an example of how we can describe a solution in terms of how
much solute and solvent are in that solution. A concentrated solution has a lot of solute as compared to solvent. A dilute solution has little solute as compared to solvent.
We use many different units to express concentration. The most common one we will use is mol/L.
Perform a web search on the following units, define what the unit means in long form and give an example of where it might be used.
- g/L
- % w/v
- % v/v
- ppm
- ppb
- mol/L
especially a solution or mixture. (ie. the amount of solute in a given amount of solvent).
If you look at the label of a juice container, you will probably see the words "juice from concentrate" or "frozen concentrated orange juice". This is an example of how we can describe a solution in terms of how
much solute and solvent are in that solution. A concentrated solution has a lot of solute as compared to solvent. A dilute solution has little solute as compared to solvent.
We use many different units to express concentration. The most common one we will use is mol/L.
Perform a web search on the following units, define what the unit means in long form and give an example of where it might be used.
- g/L
- % w/v
- % v/v
- ppm
- ppb
- mol/L
The videos below explain how to perform molarity calculations.
After watching the videos attempt the practice problems below. (answers are provided in brackets)
After watching the videos attempt the practice problems below. (answers are provided in brackets)
1. Calculate the concentration of a sodium chloride solution if 0.200 moles is dissolved in 250 mL of solution.
(0.800 M)
2. What volume of a 1.25 mol/L solution contains 5.00 moles of solute?
(4.00 L)
3. How many moles of solute are needed to make 400. mL of a 2.25 mol./L solution?
(0.900 moles)
4. What mass of sodium chloride is needed to make 0.250 L of a 0.100 mol/L solution?
(1.46 g)
5. What is the molar concentration of a solution of copper (II) sulfate if 50.0 g is dissolved in 600 mL of solution?
(0.522 M)
This next video includes examples of ion concentrations in solution.
Recall, all ionic compounds dissociate into component ions when they dissolve in water.
ex. AgNO3 dissociates into Ag+ ions and NO3- ions
After watching the video, practice on the questions below. (answers are in brackets).
Recall, all ionic compounds dissociate into component ions when they dissolve in water.
ex. AgNO3 dissociates into Ag+ ions and NO3- ions
After watching the video, practice on the questions below. (answers are in brackets).
6. What is the concentration of chloride ions in a 0.200 mol/L solution of aluminum chloride?
(0.600 mol/L)
7. What mass of copper (II) nitrate is needed to make 2.50 L of a solution that has a nitrate ion concentration of 0.100 mol/L?
(23.4 g)
The following video explains the proper way to prepare a solution.
Record the steps.
Record the steps.