Dissociation/
Van't Hoff/
Colligative Properties
Van't Hoff/
Colligative Properties
What is the Van't Hoff Factor for the following compound?
Ca(NO3)2
What is...
3 particles
Ca(NO3)2 --> Ca+2 + 2 NO3-1
When you crush up a solid compound (using a mortar and pestle) are you:
increasing or decreasing the surface area
AND
Does this increase or decrease the RATE of solubility
What is...
Increases the surface area.
Increases the RATE of solubility
What term means the substance that is dissolved in a solution?
What is...
Solute
(Make sure to be able to distinguish solute, solvent, soluble, miscible, immiscible, insoluble, solubility, saturated, unsaturated, supersaturated...)
If water boils at 100º C, and a 12M baking soda solution has a boiling point of 112ºC...what is the boiling point of a 12M salt solution?
What is...
112ºC
**Why? colligative properties
In a dilution, does the amount of solute in the solution change?
(Yes/No)
What is...
No. The amount of solute stays the same but the concentration (and amount of solvent) change.
What are two major Colligative properties we discussed?
AND
Do these properties depend on the type of substance dissolved? OR the concentration of the particles dissolved?
What is...
Freezing/Melting Point Depression AND Boiling point elevation
The concentration of the particles
What are the 3 factors affecting the RATE (how fast) at which something dissolves?
What is:
Stirring
Surface Area
Temperature
If electrolytes and non-electrolytes are dissolved in two different beakers, which one should conduct electricity?
What is...
The one containing the electrolytes.
what is the molarity of a solution that has 0.87 moles of NaCl dissolved in 87 Liters of water?
What is...
0.01M NaCl
Think solubility curves.
30 grams of KNO3 are dissolved at 70º C. You plot this point on your solubility curve and it is below the solubility curve. Your solution is...
(saturated, unsaturated, supersaturated)
What is...
Unsaturated.
What is the dissociation equation for the following compound after it dissolves in water?
Na2SO4
What is...
Na2SO4 --> 2Na+1 + SO4-2
As the pressure above a liquid decreases, what happens to the solubility of gases?
(increase/decrease)
What is...
The solubility will DECREASE
What term describes how much of a solute is dissolved in a given amount of solvent?"
(Ex. molarity, molality, percent by mass are all ways to calculate the ____________)
what is...
concentration
Dilutions:
200mL of a 13.5M solution are diluted with 500mL of water to give a new volume of 700mL, what is the new concentration of the solution?
What is...
3.86M
Which of the following compounds will NOT dissolve in water? (Hint: Like dissolves like)
Na2SO4 Cl2 NaCl
What is...
Cl2 --> This is a non-polar compound (symmetry and electronegativity of covalent bond)
3M NaCl 3M BaBr2 3M sugar (C6H12O6)
What is...
3M BaBr2...The Van't Hoff factor is 3, meaning there is the highest concentration of particles in the solution, meaning the boiling point of this solution will have increased the most.
As Temperature increases, how is the solubility of BOTH solids AND gases impacted?
Solubility of solids increases
Solubility of gases decreases
(ex. hot chocolate; ex. soda)
Given that you have a test tube at room temperature with a clear amount of precipitate (solid) resting at the bottom, what kind of solution do you have?
(saturated, unsaturated, supersaturated)
What is...
Saturated
**Unsaturated solutions will not have any precipitate resting at the bottom of the solution.
Molality:
If you want to create a 2.3 Molal solution using 10 grams of NaCl, how many grams of water would you need?
(Make sure to convert to grams after solving for kilograms)
What is...
74.3 grams of water (0.109 kg)
What are the 3 main ions responsible for cellular communication (muscular/nervous systems)?
What are...
K+, Cl-, and Na+
Explain:
What is the MAJOR difference between ionic solutes and covalent solutes after they dissolve in water?
Ionic compounds will dissociate into individual ions. (The individual atoms will literally be pulled apart due to water's polar nature.) Covalent compounds will dissolve into individual molecules but will NOT dissociate into the individual atoms that compose those molecules.
Using your understanding of polar and nonpolar compounds, explain why water and oil do NOT mix.
Like dissolves like...
Water is polar. Oil is non-polar. Because the polarities are different, the compounds will not want to mix (and as a result are not miscible).
What is the definition of a solution?
A homogenous mixture of two or more compounds in a single state.
For the following reaction, we have 2L of a 3M NaOH solution and excess hydrochloric acid, how many grams of water are produced in the solution?
NaOH + HCl --> H2O + NaCl
What is...
108 grams of H2O
Describe how each of the following phase changes are affected (raised or lowered) when salt (or any solute really) is added to water. Hint: Think of the Colligative Properties.
Condensation, Vaporization, Melting, Freezing
What is...
Freezing and Melting point temperatures are both lowered. Condensation and Vaporization points are both raised.