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Chemistry Homework Help => AP Chemistry => Topic started by: Harini on October 09, 2022, 02:16:05 PM

Title: Word Problem
Post by: Harini on October 09, 2022, 02:16:05 PM
Idk what category this question falls however I really need help understanding this. I don't understand this

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Title: Re: Word Problem
Post by: chenbeier on October 09, 2022, 08:09:47 PM
Why is it a word problem.
Calculate the mass of the given volume of phosphoric acid. Convert this to 100%. With the molar mass you get the moles. The same you do for the hydroxide.  According the chemical reaction you can see 1 H3PO4 need 3 OH-. So that means ratio is 1:3.
Title: Re: Word Problem
Post by: uma on October 10, 2022, 11:27:52 AM
Quote from: Harini on October 09, 2022, 02:16:05 PM
Idk what category this question falls however I really need help understanding this. I don't understand this
Use Density = mass / volume to know mass of 10mL of solution. Now in this mass 91.7% is H3PO4 .Follow these steps
(density x volume ) g of solution --------> 91.7% of grams of solution is mass of H3PO4 -------> moles of H3PO4 --------> moles of NaOH -------> grams of NaOH reacted with H3PO4
Mass of NaOH left unreacted is 20.0 g - mass of NaOH reacted with acid.