00:01
So we've got a balanced equation for dissolving gold in a couple of concentrated acids.
00:06
We're going to try to figure out what the stoichiometric ratio of those acids should be.
00:10
Well, we're going to get that right from the balanced equation.
00:13
The parts of the balanced equation that we need are the four chlorides and the one nitrate.
00:21
So this chloride is coming from the hcl, and this nitrate is coming from the hn .o3.
00:28
So that 4 to 1 ratio tells us that i need 4 moles of hcl for every one mole of hn -o -3.
00:41
Now we're going to see if we can find the volumes that we need to react with 25 grams of gold.
00:50
So we're going to change grams of gold to moles of gold.
00:58
And then we're going to change moles of gold to moles of chloride.
01:05
And that's a 4 to 1 ratio from our equation that was given.
01:09
And the molar mass here is 196 .97.
01:13
So that's going to give us our moles, 0 .508 moles of chloride...