Identify a specific topic from Chapter 12 that you are having a bit of difficulty with. The next person to respond should address that problem to the best of their ability and then identify their own issue.
If you haven't noticed, I will kibitz just to make sure that we are keeping on track. You might find it useful to go back in after you have posted to read everyone's postings and comments.
So I will start the process off:
"John" says that he is having difficulty with understanding the concept of how an insoluble solute affects the vapor pressure of a solution.
So I will start the process off:
"John" says that he is having difficulty with understanding the concept of how an insoluble solute affects the vapor pressure of a solution.
First notice that we are discussing the vapor pressure of a solution not a pure substance as we were in Chapter 11 and we will look at solutions made only from nonvolatile solutes so that it is only the solvent that will be entering the vapor phase. At a particular temperature, a solvent has a certain amount of energy and there is a subset of the solvent molecules that have enough energy to enter into the vapor phase. When we add a nonvolatile solute and make a solution, those solute particles physically get in the way of the solvent molecules escaping into the vapor phase. Thus a smaller number of solvent molecules can evaporate at any given temperature and the vapor pressure will decrease with the addition of a nonvolatile solute.
A problem that I might have as a student: I am having a little difficulty with understanding the relationship between saturated solutions, supersaturated solutions and dynamic equilibrium.
(Now the next person explain this to me and then list your own issue)
A problem that I might have as a student: I am having a little difficulty with understanding the relationship between saturated solutions, supersaturated solutions and dynamic equilibrium.
(Now the next person explain this to me and then list your own issue)
Dynamic equilibrium occurs when the rate of dissolution equals the rate of recrystallization. A saturated solution means that the dissolved solute is in dynamic equilibrium with the solid (undissolved) solute. Supersaturated solutions are not in dynamic equilibrium because there is an excess of solute and it will normally precipitate out of the solution.
ReplyDeleteI'm having trouble understanding the difference between nonelectrolytes, strong, moderate and weak electrolytes and what that means exactly for the solution it will form.
I actually stayed after lecture to ask about this since I struggled with this topic in C105. From my understanding, nonelectrolytes do not ionize in a solution and electrolytes, depending on the strength, do ionize to an extent. A strong electrolyte will completely ionize where as the weaker the electrolyte the less it ionizes in a solution.
ReplyDeleteI also asked about what determines whether a substance is a nonelectrolyte or an electrolyte and what determines the strength of the electrolytes but I haven't had much of a chance to go back and review my 105 notes so I guess that would be where I'm currently struggling the most for now.
Electrolytes like to break up and are usually acids, bases and salts. Acids release H+ while bases release OH-. These are cations and anions that go into the solution. This is why strong acids and bases are easily dissolved in a solution while weaker ones are not. Salts are also electrolytes because they like to release their charged ions in to the surrounding polar solution. Like dissolves like. When these electrolytes are floating around in the substance they conduct electricity because of all the charged ions. Strength is dependent on how well they break up into the aqueous solution. Weak acids don't break up completely so they are weaker electrolytes. Same goes for bases. Salts are weak when they are combined with weak acids and bases. Same rules apply for strong ones.
ReplyDeleteElectrolytes conduct electricity when they break up into positively and negatively charged ions.
They are acids, bases, and salts.
Strong bases: KOH LiOH NaOH
Strong acids: HI HBr HCl HClO4 HNO3 H2SO4
My problem is knowing which steps to work out in the actual problems. I understand the equation but I could really uses a step-by-step guide on how to do the bluebook problems on cubic cells and specific heat.
Check out the bluebook problems posted under the resources tab. They have solutions at the end of the file.
DeleteIf the next person could give some guidelines that they find useful for Taylor.
DeleteUnder the resources tab in the critical thinking folder, I have posted a guide that might help with the enthalpy problems from Chapter 11. The cubic cell problems: you need to know the radius of the atom to the length of the unit cell for each of the different types of unit cells and then you can use the standard concepts of density, mass, volume (and volume of cube = l^3) molar mass, and Avogadro's number to convert between different parts of the problems
DeleteThanks for your responses.
ReplyDelete