(a) A 0.1044-g sample of an unknown monoprotic acid requires
22....

Question

(a) A 0.1044-g sample of an unknown monoprotic acid requires 
22.10 mL of 0.0500 M NaOH to reach the end point. 
What is the molar mass of the unknown?

Accepted Answer

Hello. Everyone in this video, we want to go ahead and calculate for the molar mass of an acid. So first of all we didn't want to say that the product asset that we're dealing with here. So let's actually write this out the mono product acid. We'll just write that as H. A. To make our largest easier here. And the reaction that we're dealing with is when R. H. A. Which is acquis reacts with R. K. O. H. Which is also Aquarius to go ahead and produce a K. A. Which is a quiz as well as our H 20. Which is in its liquid state. So we're doing penetration here and we can go ahead and write that the moles of acid equal to the moles of base. And mathematically that is because the more clarity of my acid multiplied by my content or the volume of my acid, it's going to equal to the molds of acid. So doing the same thing here for the moles of base. So the concentration of my base multiplied by my volume of my base is equal to the multi base. Alright, let's go ahead and start my dimensional analysis to go ahead and actually calculate for my moles of acid. So starting off my dimensional analysis, we're going to go ahead and use the volume of the K. O. H solution given to us in the problem that being a value 25. mL. I want to go ahead and convert this into leaders. So for everyone there there's 1000 mL and next conversion we want to use for this dimension analysis process is going to be the polarity of the K O. H solution. Again, that's given to us in the problem. So we will have 0.650 moles of this K O H over one leader. We can see now that the male layers will cancel. Leaders will cancel leaving us with the molds of K. O. H. So putting these American values into my calculator, I'll get the value of 1. times 10 to the -3 moles. So again, we said that the most acid equals to the molds of base. And although we have the most of K O H, which is our base, it's equal so our mole of acid is equal to this right here. So let's go ahead and scroll down again. So we know for our molar mass, that's when. So let's write this out, molar mass is equal to moles or sorry, the mass over moles. So in our case our mass is going to be of grams. So molar mass is equal to 0.2001 g, divide by moles which we just all for to be 1.6445 times 10 to the negative three moles. Putting this into my calculator, I'll go ahead and get that the molar mass is equal to 1 g per mole. And this right here is going to be my final answer for this problem. Thank you all so much for watching.

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