Chem 102 Final
Shared Pairs
1/2(ER-VE)
Planck's constant
6.626 x 10^-34
frequency and wavelength equation
C=wavelength*frequency
Which of the following equations correctly gives the cell potential?
Ecell = Ecathode − Eanode
Electrons required (ER)
H*2 + Everything else*8
What is the effect of raising the temperature of a system at equilibrium?
It shifts the equilibrium toward the higher energy side of the equilibrium.
Conjugate acid-base pairs differ by which one of the following?
a proton
What produces hydrogen gas in this experiment?
all the reducing agents
ν
frequency
λ
wavelength
Safety glasses or goggles...
will be provided to students on the first day of lab.
A buret should be read to which nearest mL?
0.01 mL
Valance electrons (VE)
Sum of group # - Charge
A chemical species that gets reduced during a chemical reaction:
changes to a more negative oxidation state. gains electrons has a low energy unfilled orbital obtains e from a reducing agent is an oxidizing agent
What phrase best describes the lead wire?
dull gray and very bendable
Anions are _____ than the elements they form
larger
c
speed of light
1000 mmol
1 mol
c solutions have a hydronium concentration, [H3O+ ] that is which of the following?
> e−7 M
What is a reversible reaction?
A reversible reaction is one that can proceed in either direction because reactants are not completely used to form products
Which of the following is NOT true about a net ionic equation?
All ionic species in the reaction mixture are shown.
Energy equation
E=hv
When is equilibrium established?
Equilibrium is established when the rates of the forward and reverse reactions are equal.
How should accidents be prevented when working with the reactions that produce hydrogen gas, which is flammable?
Keep reactions away from ignition sources, and rinse metal before discarding it.
When operating the centrifuge, students should do which of the following?
Make sure that the lid is completely shut and the safety knob is turned to engage the safety switch. Centrifuge for approximately 30 seconds.
What should you do when filling a buret?
Make sure there are no air bubbles left in the buret tip. Make sure the stopcock is closed. Condition the buret first. Fill the buret and drain to exactly the zero mark, as this particular experiment involves volume entry into MicroLab.
Macid = molesacid / Vanalyte
Molarity of acetic acid in vinegar
When placing test tubes in the centrifuge, what are the best practices?
Never put stoppers or other items in the centrifuge with your tubes. Place test tubes containing approximately equal volumes in opposite positions on the rotor.
Proper attire for lab includes which of the following?
Pants that extend to the ankle A shirt and pants that overlap 6 inches to cover the torso A shirt that covers the shoulder and extends below the waist Shoes that cover the toes and ankles
When working with the hotplate, which of the following precautions should be taken?
Remember that it will stay hot after it's turned off — check before touching it. Keep flammable materials (including paper, hair, and clothing) away from it.
If one spills hydrochloric acid on one's hands, what is the FIRST thing one should do?
Rinse hands under running water
When the procedure says "condition the graduated cylinder with vinegar before using it", what does that mean?
Rinse with vinegar solution several times.
When working with a Bunsen burner, which of the following precautions must be observed?
The area above the burner must be clear before it is lit. The burner must never be left unattended. The substance being heated should never be pointed at people. Flammable liquids should never be heated with a Bunsen burner. If the flame blows out, the gas must be turned off, because gas could accumulate and an explosion could occur. The area near the burner should be clear of paper and other flammables.
Choose all of the following that are true about the endpoint of the titration.
The solution will change to faint pink for at least 30 seconds. The amount of analyte equals the amount of titrant added.
Which of the following is true about weak acids?
They have a small Ka and dissociate to only a small degree.
When the centrifuge process is complete, students should do which of the following?
Wait for the rotor to come to a complete stop before attempting to remove your test tubes. Using the eyehole on top, monitor the spinning rate and open the lid only after the rotor has slowed significantly.
What should be done to avoid exposure to the vapors?
Work with it under a hood and avoid inhaling the vapors.
Twisting the sleeve to open the holes (baffles) above the base of the burner does which of the following?
allows more air (oxygen) into the flame
If you condition the receiver beaker with the analyte solution prior to adding the measured volume of analyte to be titrated, what is the effect?
an overestimation of the number of moles of analyte present an increase in the volume of the titrant required to reach the end point
If you rinse your buret with deionized water, but do not condition with the titrant solution, what is the effect?
an overestimation of the number of moles of analyte present an increase in the volume of the titrant required to reach the end point
In the lab, a student must wear safety glasses or goggles...
at all times
Sodium hydroxide (NaOH) is listed as which of the following?
corrosive
When an ordered arrangement of particles extends over a long distance in a solid, the material is considered
crystalline
Simple
cubic unit cells have identical particles on all corners of the cube.
Body-centered
cubic unit cells have identical particles on all corners, and in the center.
Face centered
cubic unit cells have identical particles on all corners, and on all faces of the cube.
Which of the following are attributes of a well-prepared graph?
drawn as large as possible numerical labels on the axes small dots exactly at the positions of the data points a title labels on the axes, with units
If ΔH is positive, the reaction is
endothermic
The amount of heat energy given off or absorbed by a process at constant pressure is the change in
enthalpy
If a process is spontaneous and endothermic, the change in ______ must be positive
entropy
is related to the number of ways the energy of the system can be distributed.
entropy
A reaction that gives off heat energy is
exothermic
In a non spontaneous process _____ _____is the amount of energy that must be supplied to cause the process to occur.
free energy
ΔG is the symbol fo
free energy
Which two quantities are inversely proportional to one another?
frequency and wavelength
A chemical species that gets reduced during a chemical reaction:
gains electrons.
A solution's pH is a measure of what?
hydronium ion concentration
The ordered arrangement of particles is called
lattice
mass %
mass of acetic acid in sample/mass of vinegar *100
gacid = MWacid x molesacid
mass of acid
In what order should the readings be listed in Data Table B2?
most negative to positive
If ΔH is greater than zero, and ΔS is less than zero, the process is always
nonspontaneous
In the flame test experiment, you will be working with two types of hazard. Which are they?
open flame hydrochloric acid, corrosive solution
An alternate name for the simple cubic unit cell is the
primitive
Cations are _____ than the elements from which they form.
smaller
Because acid-base reactions are highly exothermic, which of the following should you NOT mix together?
solutions with concentrations greater than 0.1 M
A reaction in which ΔG is negative is
spontaneous
The part of the universe that interacts with a thermodynamic system is the
surroundings
is the part of the universe being studied.
system
The valve on the bottom of the burner controls which of the following?
the gas flow
What is the hottest part of a Bunsen burner flame?
the tip of the inner, dark blue cone
Temperature changes will be measured with
thermistor
Why is it important to "wash" a precipitate with water?
to remove soluble ions to prevent false tests later in the experiment
The _______ is the smallest repeating three-dimensional array that includes the stoichiometry of the compound as given by its empirical or molecular formula.
unit cell
In what units will the cell potential be measured in?
volts
When cleaning the wire between flame tests, most of the cleaning is accomplished when?
while rinsing the wire with acid