<p>Hi All</p>
<p>My son has SAT2 Chem tomorrow, here are few questions he is struggling and want to know answers </p>
<ol>
<li>When chlorine gas and hydrogen gas reacts to form hydrogen chloride, what will be the change of enthalpy of the reaction ? (bond energies are at the end of the tests)</li>
</ol>
<p>In the table listed - "Cl-Cl" -> 240 and "H-Cl" -> 430 and "H-H" 435</p>
<ol>
<li><p>How much heat is required to the temp of the 85 gms of water from 280K to 342K</p></li>
<li><p>What is the voltage of the voltaic cell Zn|Zn^2+||Cu^2+|Cu at 298K if [Zn^2+] = 0.2M and [Cu^2+] = 4.0M</p></li>
</ol>
<p>Cu^2+ + 2e^- --> Cu E^o = +0.34V
Zn^2+ + 2e^- --> Zn
E^o = -0.76V
[Note E= E^o - (0.0591/n)(log Q) ]</p>
<ol>
<li><p>Substance X has three common isotopes: X-48, X-49 and X-51. If the relative abundances of these three isotopes are 42%, 38% and 20% respecitively, what is the atomic mass of substance X ?</p></li>
<li><p>T/F Question</p></li>
</ol>
<p>Ai^3+ + 3e^- --> Ai is a correctly balanced oxidation reaction </p>
<p>BECAUSE</p>
<p>Ai^3+ + 3e^- --> Ai correctly demonstrates conservation of mass and conservation of charge.</p>
<p>Thanks you all !</p>
<p>Mwahal</p>