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Triprotic Acid

  • Thread starter sunfire249
  • Start date
  • #1

Homework Statement


Grapefruit juice contains approximately 0.75g/oz of citric acid (H3C6H5O7(aq)), a triprotic acid. If one tablet of Tums contains 500mg of CaCO3, would one tablet be able to neutralize the acid in one glass of grapefruit juice (8.0oz)? Show your calculations.

Therefore I found the relavant variables would be:
- 0.75g/oz of citric acid
- the fact that it's a triprotic acid
- the volume of one glass of grapefruit juice (8.0oz)
- the grams of tums (0.5g CaCO3)


Homework Equations


- Balancing the equation, which I had no idea how to do. I attempted to use the products H2O + CO2 + CaO, but I found I couldn't balance it.
- Dimensional analysis of the citric acid and CaCO3 from grams to moles


The Attempt at a Solution


1) Multiplied 0.75g/oz of Citric acid with the volume of citric acid (8.0oz) to get the grams of citric acid in grapefruit juice
2) I converted it to the moles of citric acid by dividing by the molar weight
So: 6.0g citric acid/193.1241g citric acid
3) I converted the amount of CaCO3 to moles as well

Not entirely sure where to go from here.
 

Answers and Replies

  • #2
symbolipoint
Homework Helper
Education Advisor
Gold Member
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1,060
Let us straighten this part first:

2. Homework Equations
- Balancing the equation, which I had no idea how to do. I attempted to use the products H2O + CO2 + CaO, but I found I couldn't balance it.
- Dimensional analysis of the citric acid and CaCO3 from grams to moles
You want to use CaCO3 to neutralize the triprotic citric acid. We could abbreviate the anion as something and say, the acid is symbolized as H3A.

Now, you want to balance CaCO3 + H3A -----> Ca... you may need to work a bit to show the actual products of the reaction. I will go ahead with this anyway.

CaCO3 + H3A -------> Ca3A2 + H2O, but beware, I have NOT yet balanced the reaction, and I may possibly be incorrect in the Ca3A2 product. The reason is that I am not sure how likely the third proton of citric acid would be neutralized.
 
  • #3
Borek
Mentor
28,396
2,799
I guess question wants you to assume neutralization goes to completion. In reality that's not exactly true.
 

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