<p>Do we have to know electroplating and electrolysis cell for the Chem SAT II?</p>
<p>electroplating no, but electrolysis yes.</p>
<p>Basically have to know that galvaniac cells(also known as volataic cells) PRODUCE energy which electrolysis cells NEED energy for the reaction to occur.</p>
<p>Understand the principle of electroplating. It almost definitely won’t be on the test, but it’s still good to know.</p>
<p>Everything shaheiruddin said is right, just the names are spelt slightly differently (galvanic and voltaic, not galvaniac and volataic), but that’s not a big deal. Just know that, in electrolysis cells, reactions that normally aren’t spontaneous are forced to occur. For instance, the reaction of oxygen molecules with hydrogen ions is spontaneous - it forms water.</p>
<p>O2 + 4H+ + 4e- —> 2H2O </p>
<p>The standard reduction potential of this reaction is +1.23. Because this is a positive value, the reaction is spontaneous.</p>
<p>However, in an electrolysis cell, an electric current is run through a sample of water, thus providing enough energy to force the sample to react in an otherwise impossible way.</p>
<p>2H2O —> O2 + 4H+ + 4e-</p>
<p>ok thanks!</p>