Critical Thinking
What does the salt bridge do in an electrochemical cell?
Allows for the continuous flow of electrons in the electrochemical cell
When a battery is being charged, what kind of reaction is occuring?
Electrolytic reaction
When a battery is discharging (being used), what kind of reaction is occuring?
Electrochemical reaction
Why do we use dry cells in most electronics (cell phones, computers, electronic watches, etc.)?
Because dry cells have no fluids that might short circuit electronic circuit boards and other circuits.
What causes all of the real changed that occur in a chemical reaction?
In the electrolysis of water, what should be the ratio of the products made?
Which electrochemical cell would produce more Volts?
F, F+ and and Li, Li+
or
Cl, Cl- and Cd, and Cd+2
Cl, Cl- and Cd, and Cd+2
What does changing the electrolyte concentration do to the volts produced by electrochemical cells?
Increasing the concentration would increase the volts produced, decreasing the concentration would decrease the volts produced.
One voltaic cell with electrolyte concentrations of 1M produces .75Volts.
Another voltaic cell with electrolyte concentrations of 1M produces .50Volts.
If you increased the electrolyte concentrations of the second cell to 2M, would the second cell or first cell produce more Volts
If you increased the concentration to 2M, you would double the Volts produced. So you would have 1.00 Volts. The second voltaic cell would produce more volts.
What would be the Voltage made from:
Zn, Zn+2 and Cu, Cu+2
Cathode: Cu+2 +2e- => Cu0
Anode: Zn => Zn+2 + 2e-
1.10 Volts
Cathode: Cl0 + e- => Cl-
Anode: Na0 => Na+ + e-
However, how many electrons are actually transferred in the synthesis of Na and Cl?
2 Electrons
You often hear that battery acid is toxic and if you see it leaking you should dispose of the battery safely and responsibly. What actually is the battery acid?
The aqueous solution containing ions that drive the electrochemical cell of a battery.
A reaction is performed. The chemist who performed the reaction and analyzed the only real change that occurred during the reaction was some atoms of element "X" went from a charge of zero to a charge of one. Was the chemist's reaction a redox reaction?
No, he only had an oxidation. There was no reduction in the reaction. To be classified as a redox reaction, you must have one piece be oxidized and one piece be reduced.
The cathode should have been her necklace, the anode should have been a piece of gold metal.
What is the main difference between electrolytic and electrochemical cells?
Electrolytic cells need an outside source of energy while electrochemical cells produce electricity.
What do half reactions and net ionic equations show?
The transfer of electrons, the real change occurring in a reaction.
Brent wants to make an electrochemical cell using Nickel and Silver. He grabs the compounds nickel nitrate and silver chloride to perform his reaction. His reaction produces no volts, meaning he must have set up something wrong. What critical error did Brent make.
You can ask for one hint to receive 400 points instead of 500 for this question.
Brent used silver chloride which is insoluble in water. So Brent had little to no silver ions. Electrochemical cells only work with ions, not solid compounds.
What would be the Voltage of a cell made from:
Ag, Ag+ and Ni, Ni+2
Cathode: 2Ag++ e-=> 2Ag0
Anode: Ni0=> Ni+2 + 2e-
2(.80) + 26 =
1.86 Volts
What would be the Voltage of a cell made from
Cu, Cu+2 and Na, Na+ ?
Cathode: Cu+2 + 2e- => Cu0
Anode: 2( Na+ + e- => Na0)
.34 + 2(-2.71) = -5.08Volts
In electrolytic cells, an electric current is applied to separate two (or more) elements in a compound into the their pure elemental forms. Why do you need a relatively large amount of electricity to break apart compounds?
Most things in nature exist as compounds. Compounds are more stable than pure elements more often than not. It is against the "natural law" to have pure elements.