00:01
To determine the concentration of calcium, we recognize that calcium will react in a one -to -one fashion with edta in order to make the complex ion, ca, edta, and typically, edta will have a 2 -minus charge, so this will end up being neutral.
00:31
So if we titrate 50 milliliters of the unknown solution with 0 .025 molar edta, and it requires 16 .85 mill liters of edta, we can convert those mill liters into liters by dividing by a thousand, and then convert the liters into moles using the molarity.
00:57
1 liter has 0 .0250 moles edta.
01:04
And then because the reaction is 1 to 1, 1 mole, edta reacts with 1 mole calcium ion.
01:17
Now knowing the moles of calcium ion to determine the concentration of calcium in the unknown, we simply divide that by the volume in order to get molarity.
01:31
But i think it wants ppm...