Can Anyone Help Me With this 1999 AP Chemistry Free-Response Question...Thanks A LOT

Test Preparation AP Test Preparation
1

<h2>How do I approach this and what are the answers? Thanks so much</h2>

<p>Answer the following questions regarding light and its interactions with molecules, atoms, and ions.</p>

<p>1.</p>

<pre><code> The longest wavelength of light with enough energy to break the Cl-Cl bond in Cl2(g) is 495 nm.
</code></pre>

<p>1.</p>

<pre><code> Calculate the frequency, in s-1, of the light.
</code></pre>

<p>2.</p>

<pre><code> Calculate the energy, in J, of a photon of the light.
</code></pre>

<p>3.</p>

<pre><code> Calculate the minimum energy, in kJ mol-1, of the Cl-Cl bond.
</code></pre>

<p>2.</p>

<pre><code> A certain line in the spectrum of atomic hydrogen is associated with the electronic transition in the H atom from the sixth energy level (n = 6) to the second energy level (n = 2).
</code></pre>

<p>1.</p>

<pre><code> Indicate whether the H atom emits energy or whether it absorbs energy during the transition. Justify your answer.
</code></pre>

<p>2.</p>

<pre><code> Calculate the wavelength, in nm, of the radiation associated with the spectral line.
</code></pre>

<p>3.</p>

<pre><code> Account for the observation that the amount of energy associated with the same electronic transition (n = 6 to n = 2) in the He+ ion is greater than that associated with the corresponding transition in the H atom.
</code></pre>

2

<p>I am too lazy to find you the actual answers.</p>

<ol>
<li>c = wavelength * frequency</li>
<li>E = hf</li>
<li><p>You know how much energy you need to break one bond...how much do you need to break a mole of bonds? (I think.)</p></li>
<li><p>The atom is going from a higher energy level to a lower energy level, so it emits energy. This is analogous to dropping a ball from the top of a building -- you're dropping it from a place of higher potential energy to lower potential energy, so the lost energy goes into kinetic energy. Except here the lost energy goes into light.</p></li>
<li><p>There's a formula that gives you the energy value of each energy level for the hydrogen atom. Use that, then use E=hf and c=freq(wavelength).</p></li>
<li><p>The electric potential energy associated with two charged particles is kq1q2/r, where q1 and q2 are the electric charges of the particles and r is the distance between them. So the difference in energy between n=6 and n=2 = kq1q2(1/r6 - 1/r2). So the larger q1*q2 is, the greater the amount of energy associated with the transition. A He+ nucleus has a greater electric charge than a H nucleus, so the difference will be greater. (I don't remember if this is how chemistry teaches you to do it, but it's from physics and it makes sense.)</p></li>
</ol>