A 0.2800 g sample of an unknown acid requires 28.22 ml of 0.1199 M NaOH for neutralization to a phenolphthalein end 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 am doing this right, I found a.) to be .003384 mols of OH- by:
28.22 ml of NaOH= .02822 L of NaOH x .1199 M NaOH x (1 mol OH-/1 mol Na+)= .003384 mols OH-. Is that correct? If so, I still have no idea where to start on the following questions. Any guidance would be greatly appreciated.

a. correct

b. mols OH^- = mols H^+
c. mols = grams/molar mass. you have mols and grams, solve for molar mass.
Technically you must know if this is a monoprotic, diprotic or triprotic acid.

a.) Yes, you are correct in finding the moles of OH-. Well done!

b.) Since the acid and base react in a 1:1 ratio, the moles of H+ in the acid will be the same as the moles of OH-. Therefore, the moles of H+ will also be 0.003384 moles.

c.) To calculate the molar mass of the unknown acid, you need to use the moles of the acid and the mass of the acid sample. In this case, the mass of the acid sample is given as 0.2800 g.

Molar mass (g/mol) = Mass of the acid (g) / Moles of the acid (mol)

So, in this case, the molar mass would be:

Molar mass = 0.2800 g / 0.003384 mol

Calculating this will give you the equivalent molar mass of the unknown acid.

I hope this guidance helps! Remember, chemistry can be a bit acidic, but it can also be quite basic. Just keep balancing those equations and remember to have fun with it!

Yes, your calculation for part a) is correct. You have correctly determined that there are 0.003384 moles of OH- used.

To find the number of moles of H+ in the acid, we can use the concept of stoichiometry. The balanced chemical equation for the neutralization reaction between the acid and NaOH is:

H+ (aq) + OH- (aq) -> H2O (l)

From the equation, we can see that 1 mole of H+ reacts with 1 mole of OH-. Therefore, the number of moles of H+ in the acid is also 0.003384 moles.

Now, to calculate the equivalent molar mass of the unknown acid (the molar mass of the acid that provides one mole of H+) we can use the formula:

Equivalent molar mass = Mass of acid (g) / Moles of H+

Given that the mass of the acid is 0.2800 g and the moles of H+ is 0.003384 moles, we can substitute these values into the formula:

Equivalent molar mass = 0.2800 g / 0.003384 mol

Calculating this will give us the answer for part c).

Yes, you have correctly calculated the number of moles of OH- used in the neutralization reaction. To answer the rest of the questions, we can use the stoichiometry of the balanced chemical equation of the neutralization reaction between the acid and NaOH.

The balanced chemical equation for the neutralization reaction can be written as follows:

H+ (aq) + OH- (aq) → H2O (l)

a.) To find the number of moles of H+ in the acid, we need to use the stoichiometry of the reaction. From the balanced equation, we can see that 1 mole of H+ reacts with 1 mole of OH-. Since you have already calculated the moles of OH- (0.003384 mol), we can conclude that the moles of H+ in the acid are also 0.003384 mol.

b.) Now, we can use the moles of H+ in the acid to find the equivalent moles of the unknown acid itself. From the balanced equation, we can infer that 1 mole of H+ is equivalent to 1 mole of the unknown acid. Therefore, the moles of the unknown acid are also 0.003384 mol.

c.) To calculate the equivalent molar mass of the unknown acid (molecular weight per mole), we need to divide the mass of the sample (0.2800 g) by the number of moles of the unknown acid (0.003384 mol):

Molar mass of unknown acid = Mass of the sample / Moles of the unknown acid
Molar mass = 0.2800 g / 0.003384 mol = 82.73 g/mol (approximately)

So the calculated equivalent molar mass of the unknown acid is 82.73 g/mol.