Chemistry Help...Please!!! Final Soon

Pre-College Issues High School Life
1

<p>OK…I have a teacher that doesn’t teach, and I really need your help.</p>

<p>How do you do these problems?</p>

<li>What is the pH of a 0.5 M NH4NO3 solution?
Kb = 1.8 x 10^-5</li>
</ol>

<p>2.</p>

<p>Calculate Ksp, the solubility product, for silver bromide, if:</p>

<p>AgBr + e- → Ag + Br- (E standard = +.0732 V)
Ag+ + e- → Ag ( E standard = +.799 V)</p>

<li>When copper or nickel is electroplated with silver, the silver solution contains cyanide ion to reduce the effective concentration of Ag+ in the solution. Estimate the concentration of Ag+ in a 0.10 M solution of silver nitrate to which excess potassium cyanide (1.0 M) has been added.</li>
</ol>

<p>Kf for [Ag(CN)2]- = 1.0 x 10 ^21</p>

<p>Thanks a lot!!! I have a final tomorrow.</p>

2

<p>come one, some of you people have got to be good at chemistry!</p>

3

<p>for number one take the negative log of the Kb and then do 14- that answer to get the answer.</p>

4

<p>Hmm, taking a guess</p>

<ol>
<li>What is the pH of a 0.5 M NH4NO3 solution?
Kb = 1.8 x 10^-5</li>
</ol>

<p>NH4NO3-->NH4 + NO3</p>

<p>1e-14/1.8e-5=5.556e-10</p>

<p>5.556e-10=x^2/.5= [NH4]</p>

<p>NH4 + H2O-->NH3 + H+ and repeat above using 5.556e-10</p>

5

<p>Do what big_al said.</p>