Anatomy
The Lysis
Use(less)
Uhm
50
Define a binary compound
A compound that contains two elements chemically combined
50
What does Oxidation mean in the context of electrolysis?
A. Gaining of electrons
B. Loss of electrons
C. Gaining of oxygen
D. Loss of hydrogen
B.
Ions move to their respective electrodes, anions go to the anode and so on, to lose e- and become a neutral atom (eg. Cl-(aq)--> Cl(g) + e-)
50
What's the purpose of Electroplating?
form more corrosion-resistant and shiny products
50
How do I know this is water?
Test the boiling/freezing point (100C/0C)
100
Define an Electrolyte
The molten or aqueous substance that undergoes electrolysis
100
Between reactive and unreactive metal ions and hydrogen ions, which has the highest tendency of receiving e- (reduction)?
Unreactive, H+, reactive
100
Name an example of uses for pure copper.
Cooking utensils
Wire
100
Is bond breaking exo- or endothermic?
Endothermic
150
Define a Cathode and Anode
- Cathode: Electrode carrying positive charge
- Anode: Electrode carrying negative charge
150
Between halide ions, sulfate ions and hydroxide ions, which has the highest ease of discharge (aqueous solution)?
(+100 for putting them in order of ease of discharge?; most to least)*
OH-
I-, Br-, Cl-, (NO3-), SO42-
150
What can be observed during the purification of copper?
Pure copper Cathode gains mass and impure copper anode loses mass. Impurities left in the electrolyte
150
How do you identify the presence of hydrogen and oxygen?
using a lighted splint, squeaky pop can be heard; using a glowing splint, it will relight.
200
Define electrolysis
the decomposition of an ionic compound, when molten or in aqueous solution, by the passage of an electric current
200
In the electrolysis of dilute Sodium(II)chloride, what is produced at the cathode and anode?
Cathode: H+(g) (H+ is less reactive than Na+)
Anode: OH-(aq) (OH- is more prominent than Cl-)
200
How do hydrogen fuel cells generate energy?
Bond making of H2O (2H2 + O2 --> 2H2O) generates energy :)
200
What's a catalyst?
a substance which alters the rate of reaction and remains chemically unchanged after
250
Why must electrolytes be in molten/aqueous form?
This form allows ions to move freely and carry the current to the external circuit
250
Why can't sulfate ions (SO42-) be electrolysed?*
Sulfate and nitrate ions, compared to halide and hydroxide ions, are the lowest ease of discharge/most difficult to oxidise (no further explanation)
250
Why are hydrogen fuel cells so impractical?
- fuel being in gas at room temp.
- expensive to buy a generator
- electric motors aren't durable
250
When performing titration, how do you know that your analyte has become neutral? (alkali titrant)
Name and spell the indicator.
When the phenolphthalein becomes light pink