Solution Formation and Concentration Units
The formula for molarity and molality.
What is
M = (mol solute)/(L solution)
m = (mol solute)/(kg solvent)
Which of the following liquids has the highest vapor pressure?
(A) CH3CH2CH2CH2OH (1-butanol)
(B) CH3CH2CH2CH2CH2CH3 (hexane)
(C) CH3CH2OCH2CH3 (diethyl ether)
(D) CH3CH2CH2CH2CH3 (pentane)
(E) CH3CH2CH2CH3 (butane)
(E) CH3CH2CH2CH3 (butane)
Consider rate = k[A][B]2
This is the factor that the rate increases by if the concentration of A doubles, while the concentration of B triples.
What is 18?
The overall order of a reaction with the rate law rate=k[A2][B] is this.
What is 3rd order?
Explain why iodine is not soluble in water.
Like dissolves like. Iodine has nonpolar and will not interact with water that is polar.
The Van't Hoff factor for nickel (II) bromide.
What is i=3
Increasing the concentration of a reactant generally increases the reaction rate because of this theory.
What is collision theory?
This is the equation you would use to solve this problem. The kinetics of a gas phase reaction of the form A → Products results in a rate constant of 0.0897s-1. For this reaction, the initial concentration of A is 0.945 M. How many seconds will it take for the concentration of A to reach 0.293 M?
What is ln[A]t = ln[A]0 - kt
Come to the board and draw a simple cartoon of solution formation, including delta H signs. Then verbally explain why those are the signs.
expanding solute: delH>0
expanding solvent: delH>0
formation of solution: delH<0
Consider the imKf products below:
NaCl = 0.190
Glucose = 0.700
AlCl3 = 0.145
Rank the freezing points from lowest to higest.
Glucose, NaCl, AlCl3
Explain how to find the average rate of a reaction.
Pick the outer-most two points on a concentration vs. time graph (or use given data).
Find the change in concentration
Find the change in time between those two points.
Divide the change in concentration by the change in time:
This is the equation you should use for this problem. If a certain reaction has a rate constant of 1.10×10–4 L mol–1 s–1 at 470. oC and a rate constant of 5.70×10–4 L mol–1 s. at 500. oC, what is the value for Ea?
The Arrhenius equation with 2 k and 2 T values. (I didn't feel like typing that)
A beaker containing calcium chloride dissolving in water feels warm to the touch while holding
it. Which of the following reasons best describes this scenario?
(A) The overall solution making process is endothermic.
(B) Breaking solute-solute and solvent-solvent interactions is exothermic and forming solute- solvent interactions is endothermic.
(C) Calcium chloride dissolving in water is a combustion reaction.
(D) The solution does not form due to heat being taken from your hand.
(E) Solute-solvent interactions are stronger than solute-solute and solvent-solvent interactions
combined
(E) Solute-solvent interactions are stronger than solute-solute and solvent-solvent interactions
combined
explanation: Since the solution feels warm, the energy released by forming (-H/ exothermic) solute-solvent interactions is greater than the energy required to break (+H/ endothermic) the solute and solvent apart. This makes the overall process exothermic, which is why you feel heat.
The following diagrams represent four closed systems containing aqueous solutions of the same
nonvolatile solute at the same temperature. Which solution has the highest vapor pressure?
(slides for picture)
IV
For the reaction A + 3B --> 2C:
The rate of disappearance of B is ____ the rate of appearance of C.
3/2
Identify the error: (see slides)
-did not keep condition 1 and 2 values consistent with respective variables
- used the incorrect R value
- did not convert Celsius to kelvin