Hey you're on the tutor hotline with Melissa Maribel
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Hi Melissa, it's Michele,
can you help me with this question on writing dissociation
equations for strong electrolytes?
Of course, let's go over that.
So we're writing dissociation equations for strong electrolytes
But let's go over what a strong electrolyte is
So with this strong electrolyte
which of course these are all strong electrolytes
they completely dissociate and what dissociation refers
to is just breaking apart into
ions. So when a compound
like let's say something like this, breaks apart or
dissociates it completely breaks apart into its ions
its really similar to net ionic equations
so a type of strong electrolyte is a strong
acid or a salt. And you'll notice that all of
these are types of ionic compounds. A strong acid
is something like HCl, so in this case what
would happen, since this completely dissociates
it would break apart into its separate ions
which is Hydrogen plus or H+
and then chlorine with it's charge so -1 charge.
Same thing goes for something like this strong
acid, so nitric acid. Well I have hydrogen
so it's going to be H+. I have that nitrate ion
So that's going to be NO3 with a -1 charge
And then if I were to let's say have something that
is a salt, salt of course are
ionic compounds if you remember.
Ionic compounds consist of a metal and a nonmetal. The metal is
positively charged and the nonmetal is negatively charged.
And then of course the nonmetal could also be replaced with a
polyatomic ion, which we see here with NO3
and same thing here with NO3. So for this first one this is
a salt we have NaCl, I separate this apart
to have it be NA+, because that's the
charge of sodium and then Cl-
I'll do the same exact thing here for this other salt
where we have calcium and calcium's charge is a
2+ charge. And then nitrate has a
-1 charge but the difference here is
this subscript
There are two nitrates so I have to indicate that there are also
two NO3's
in this equation and that's what makes it balanced.
So this 3 subscript is part
of nitrate already, right knowing your polyatomic
ions is essential for these types of questions, and just
Chemistry all together, where I know NO3 is
nitrate, that doesn't mean that there's 3 NO's
this NO3 is all together but this 2
subscript on the outside of the parentheses tells me that
there are 2 nitrates
Now that we understand how to break everything apart and what a strong
electrolyte is, let's start off with part A.
Ok, so the first thing with part A, what I'm going to
do is just identify my metal and my nonmetal and
them the charges for each
So this is the metal that we have, cobalt it has a
3+ charge. If you didn't know what the charge was
for cobalt that's ok, we could actually figure it out by
just looking at this formula
This Chemical formula
Chlorine has a -1 charge
The fact that there's a 3 subscript means that cobalt's
charge must have been a 3+
So this 3 kinda goes back and it tells me that
cobalt is a 3+ charge I know that this subscript
also tells me that there are 3 chlorines
So there's 3 chlorines and chlorine has a -1 charge
How I'm going to write this dissociation equation