<span>Selenium has 6 valence electrons, shares four of them with the four F atoms and has a pair of electrons left over, so has l0 electrons in its outer energy level. Choice A</span>
You have to make an assumption or estimation here: (don't think about the 1.00 M KSCN)
Since 1.00M KSCN provides a common ion source of SCN-. Therefore, you will have a <span>1.00 M SCN-.
</span><span>[Pb+2][SCN-] ~ 0.01 x 0.02^2 = 4E-6
</span> Pb(SCN)2 <---> Pb++ + 2SCN- <span>
</span>Bringing 1.00M SCN- back in the problem. 1.00M + 0.02M, ignoring the SCN-, and calculating the <span> [Pb+2]:
</span><span>
</span><span>Ksp = [Pb++][SCN-]^2
</span>2.00E-5 = [Pb++](1.00)^2
<span>[Pb++] = 2.00E-5 M </span>
<span>The mass balance shows that: </span>
<span>[Pb++] = [Pb(SCN)2] </span>
So [Pb(SCN)2] = 2.00E-5 M in 1.00 M KSCN.
The CNO cycle<span> (for </span>carbon–nitrogen–oxygen<span>) is one of the two known sets of fusion reactions by which stars convert hydrogen to helium, the </span>other<span> being the proton–proton chain reaction. Unlike the latter, the CNO </span>cycle<span> is a catalytic </span>cycle<span>.</span>
Surface Tension. Physical science for ya there ;)