Write the name from the formula or the formula from the name
for ...

Question

Write the name from the formula or the formula from the name
for each hydrated ionic compound.
a. cobalt(II) phosphate octahydrate

Accepted Answer

Hey everyone in this example, we need to give the chemical formula for the following hydrated ionic substance, nickel to phosphate, Octa hydrate. So what we want to recognize is that this part of our name, nickel. To where to in the parentheses is telling us something and this is specifically telling us that we have a certain charge attributed to this nickel Roman Numeral two represents plus two. And if we go to our periodic tables we find nickel in the transition metal sections. So because we know that too, as a roman numeral means to or means plus two, that means that our nickel as a transition metal has a plus two charge. The next step of our chemical formula is finding out what sort of charge we have on the second part of our name, which is this, this phosphate name. So what we want to think of is our ion for phosphate. And we should recall that the phosphate ion is written out as a poly atomic ion P. 043 minus. And so we have a -3 charge associated with this eye on here. So the next step is to go ahead and crisscross these charges with one another. So we're going to have the P. 043 minus cross with our and I. Two plus charge. And so in doing so, we're going to form our poly atomic ion N. I. In parentheses we want to have P. O. And sorry and I with a subscript of three because we carry that charge from crisscrossing with the phosphate ion. And then we have our parentheses beginning with our phosphate ion P. 04 where it now has a subscript that is the nickel two plus caddy in charge. So P. 042. Our next step is to look at the last part of our name to hydrate. And so what we have is in the beginning oct we want to recall tells us a prefix and oct as a prefix means eight. So the hydrate portion of this last part of our name is referring to the water molecule H 20. And so what Octa hydrate tells us as a whole is that we have eight moles of our water H 20 molecule. And so overall we're going to go ahead and combine each of these things that we've deduced here from our name. So we have our poly atomic ion N I three P 042 from crisscrossing the charges between our two deduced ions in the name. And this is being hydrated by eight moles of water Octa hydrate. And so this is going to complete this example as our final answer here. So I hope that everything we reviewed was clear. But if you have any questions, please leave them down below and I will see everyone in the next practice video

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