A 0.2800 g sample of an unknown acid requires 28.22 mL of 0.1199 M NaOH for neutralization to a phenolphthalein point.
a.) How many moles of OH- are used?
b.) How many moles of H+ are found in the acid?
c.) What is the calculated equivalent molar mass of the unknown acid?
If I'm doing this right, I got .003384 mol OH- for question a. Here's my work:
28.22 mL NaOH x (1 L/1000 mL) x (.1199 mol NaOH/1 L NaOH) x (1 mol OH-/1 mol Na+)= .003384 mol OH-
However, assuming that is even right, I have no idea where to start on the second two questions. Any guidance would be greatly appreciated. Thank you!
Sorry for the double post. Just saw that my original question actually posted though I was told it had not.
Does that mean you saw my response? Do you have additional question on this problem?
Great job on part (a) of the question!
Now, let's move on to parts (b) and (c) of the question.
To find the number of moles of H+ in the acid, we need to use the concept of stoichiometry. We know that acid and base react in a 1:1 ratio according to the balanced chemical equation:
Acid + NaOH -> H2O + Salt
From the balanced equation, we can see that one mole of acid reacts with one mole of NaOH. Since we have determined the number of moles of OH- (0.003384 mol), we can conclude that it is equal to the number of moles of H+ in the acid.
So, the answer to part (b) is also 0.003384 mol.
Now, let's move on to part (c) - calculating the equivalent molar mass of the unknown acid.
The molar mass of a substance is the mass of one mole of that substance. In this case, we know the mass of the sample of the unknown acid (0.2800 g) and the number of moles of the acid (0.003384 mol).
The definition of molar mass allows us to find the equivalent molar mass of the unknown acid. It is calculated by dividing the mass of the sample by the number of moles:
Molar Mass = Mass of the sample / Number of moles
Plugging in the values:
Molar Mass = 0.2800 g / 0.003384 mol
Calculating this expression will give you the equivalent molar mass of the unknown acid.
I hope this explanation helps! Let me know if you have any further questions.