<p>for 1) </p>
<p>a.i) HOCl
iii) HOI is weaker</p>
<p>b) HOCl + H20 <–> H30+ + OCl-</p>
<p>c)
i) Kb= [HOCl][OH-]/[OCl-]
ii) 1x10^-14/(2.9x10^-8) = 3.4x10^-7
iii) 3.4x10^-7= x^2/1.2 = .00064M </p>
<p>d
i) 10^-(6.48)= 3.3x10^-7 M
ii) 6.48= -log(2.9x!0^-8) +log(/[A])
.088=/[A], thus more acid</p>
<p>for b) HOCl + H20 <–> H30+ + OCl-</p>
<p>What if you put HOCl +H20 <–> H+ + OCl-, will you still get the point?</p>
<p>i don’t think so. your equation is unbalanced, which is the reason why many people use
H3O+ than H+.</p>
<p>5 d:</p>
<p>This one is different right because they ask for bond energy not heat of formation
delta h=bonds broken-bonds formed (reactants - products)
delta h is positive so the bond energy of reactants must be larger than the products</p>
<p>is it ok if we didnt label what kind of K? like I simply put K = instead of Kb =</p>
<p>Whoever said I gave my answer for bond energy required in molecules, that is not what I put. Notice I multiplied (242000J/mol)(1mol/(6.022x10^23 bonds)), so the end becomes J/bond, which is what they want.</p>
<p>For 5 d. yeah it’s products minus reactants, but it’s POTENTIAL energy products - POTENTIAL energy reactants. If delta h is positive, it is endothermic. If it is endothermic, that means it absorbed energy (also got cooler). If that happens, doesn’t that energy go into the bonds? I am like 90% sure that if it’s endothermic then it absorbs bond energy. But don’t kill me if I’m wrong.</p>
<p>Because if delta h is positive, then that means it is endothermic (let’s say 50), which means that the energy is on the reactant side. In that case, if you used kinetic energy products-kinetic energy reactants, you get 0-50, which gives delta h is -50. That would mean it is exothermic. But it’s not! So it is potential energy products-potential energy reactants.</p>
<p>O hm… I never thought of it that way. I thought of it as the energy released when the bonds were broken was not as much energy stored in the original bonds of the reactants hence positive delta h</p>
<p>Would Cl2 be a zero order reactant because it doesn’t appear in the RDS?
I said methane was 1st because of the stoichiometry in the RDS</p>
<p>Someone correct me if I am wrong too.</p>
<p>Yeah reactants minus products is only if you use kinetic energy I think</p>
<p>Hm, for bond energies you use reactants - products.</p>
<p>The bond energy is a measure of how much energy it takes to break the bond, or of how much energy is released when the bond forms. Thus,</p>
<p>+reactants (positive energy going in to break the bond) - products (negative energy released when the new bonds form)</p>
<p>gives you the correct +/- terms for bond energy, as breaking reactant bonds is positive (endothermic) and forming product bonds is negative (exothermic).</p>
<p>But perhaps if you specified like such:</p>
<p>“It takes x joules to break one bond of Cl2”</p>
<p>you could bypass getting the sign wrong?</p>
<p>What is the reason that HOI is weaker? I put that, but BSed a reason why it’s weaker.</p>
<p>The trend for the halogens is the further you go down, the weaker the acid.</p>
<p>thnx for that wonderful EXPLANATION.</p>
<p>I said that it was because lower down the table there was more nuclear charge, which kept the acid from dissociating. Is this right?</p>
<p>I think it might have to do with how the electronegativity of elements going down the periodic table, but I’m not sure.</p>
<p>Hey, can somebody post the complete list of the correct answers to the free response questions? Thanks so much</p>