00:03
We are asked to find ph and we are titrating 50 .00 milliliters of 0 .0500 molar naoh with 0 .1000 molar hcl.
00:29
And first we have a 0 .00 milliliters of hcl added.
00:42
So i will have 50 .00 milliliters.
00:49
I guess i don't even need to do this.
00:54
This will be the negative log of 0 .0500.
01:01
It will be 14 minus the negative log will equal.
01:12
Whoops.
01:12
Turn this on.
01:13
14 minus parentheses negative log 0 .05 close enter will be 12.
01:25
What do i have here? tons of sig figs.
01:29
Three sig figs.
01:33
699.
01:43
Next 24 .5 milliliters.
02:03
So my total volume at this point will be 74 .5 milliliters, which is these two values added 74 .5.
02:24
And let's figure out how many moles of everything that we have.
02:29
I have 50 .00 milliliters of naoh.
02:43
This is 1000 milliliters per liter and i have 0 .0500 moles per liter will give me 0 .05 times 0 .05 will be 0 .00250 moles of naoh.
03:08
Now we added 24 .50 milliliters of hcl and it has a 0 .1000 moles per liter will equal 0 .00245 moles of hcl.
03:56
Hcl and naoh have a one to one mole ratio.
04:00
So 0 .00250 moles of naoh minus 0 .00 moles of hcl equals 5 .00 times 10 to the minus fifth moles of naoh.
04:42
Then we will divide that by 0 .07450 equals 6 .711 times 10 to the minus fourth molar...