Michael C. answered • 01/04/17
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Important points:
1) 1cm3 is equal to 1mL
2) "trioxocarbonate" (IV) solution is another name for CO32-, usually taught in chem class as one of the polyatomic anions commonly called Carbonate.
Other than that, this is a standard acid-base titration problem.
We are given the concentration of HNO3 (Molar Mass of 63.012g/mol)
.67g/100mL(1mol/63.012g) = .01mol/100mL or ultimately .1mol/Liter which is the definition of Molarity (the most commonly used concentration in Chem Lab)
There is a one to one molar relationship between Nitric Acid and Carbonate. So the number of moles of the acid reacted equal the number of moles of Carbonate that neutralized the acid.
Find the total number of moles of HNO3 reacted.
.1mol/Liter (.031Liter) = 3.1 x 10 -3 moles HNO3 which equals the number of moles of Carbonate at the end point of titration.
3.1 x 10 -3 moles CO32- / .025 L = .12 moles/Liter
Michael C.
No problem.
Molarity is defined in units of moles per liter. So we have 0.1 moles per 1 liter concentration of Nitric Acid (HNO3), which by definition is 0.1 Molar Nitric Acid.
The problem says we titrated 31cm3 which is the same as saying 31mL. I just converted 31mL to Liters so it's .031Liters titrated.
Then I just multiplied the concentration times the volume to get the number of moles.
In this problem, you could have just left the units in mL or even cm3 (which you'll rarely see volume expressed in cubic centimeters) as they cancel out in the equation. For many problems though, it's good to have a habit of converting to Liters as most problems as for the concentration specifically in molarity, as this is most likely what you'll see the concentration at in lab.
I find it's good to express it like this initially for acid-base titration problems to help keep units straight.
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01/04/17
Damilola G.
Sir I appreciate.
.1mol/Liter (.031Liter) = 3.1 x 10 -3
01/04/17