Include an explanation, balanced chemical equation, units, significant figures and/or calculations where appropriate.
Determination of the Molar Mass of an Unknown Acid
Trial 1:
0.499 g unknown acid
24.07 mL NaOH
Trial 2:
0.501 g unknown acid
23.71 mL NaOH
Trial 3:
0.500 g unknown acid
24.15 mL NaOH
Using the data presented above, calculate the molar mass of the unknown acid. Include the calculation for each trial and the average.
Is this a duplicate post? See my response below.
No, this is not a duplicate. The other question refers to molarity. This one is asking for molar mass of an unknown acid.
For this question would I do the following...
Start with the volume of NaOH then convert it to moles with the answer from the first question.
Use stoichiometry to find the number of moles of HX (unknown acid).
Then divide the mass of the acid by the number of moles of the acid to find the molar mass.
moles NaOH = M x L
You must have some knowledge about the unknown compound; I assume you were told that it took 1 or 2 or 3 moles NaOH to react with it (or the information could have been in another form such as monoprotic, diprotic, or triprotic acid).
Convert moles NaOH to moles unknown.
Then moles = g/molar mass.
You have moles and grams, calculate molar mass.
To determine the molar mass of the unknown acid, we need to use the data from the three trials and the balanced chemical equation of the reaction between the acid and NaOH.
1. Balanced Chemical Equation:
The reaction between the unknown acid (HA) and NaOH can be represented by the following balanced chemical equation:
HA + NaOH → NaA + H2O
2. Calculation for each trial:
In each trial, we are given the mass of the unknown acid and the volume of NaOH used. The volume of NaOH can be converted to moles using its molar concentration. Then, using the balanced chemical equation, we can determine the moles of unknown acid reacted. Finally, by dividing the mass of the unknown acid by the moles reacted, we can calculate the molar mass.
Trial 1:
Mass of unknown acid (HA) = 0.499 g
Volume of NaOH (V) = 24.07 mL = 0.02407 L
Using the equation Molarity (M) = moles (mol) / Volume (L), we can calculate the moles of NaOH:
Molarity (NaOH) = moles (NaOH) / V
Moles (NaOH) = Molarity (NaOH) x V
Assuming the molar concentration of NaOH is known, we can calculate the moles of NaOH used in trial 1.
Next, using the balanced chemical equation, we know that 1 mole of HA reacts with 1 mole of NaOH. Hence, the moles of HA reacted in trial 1 are equal to the moles of NaOH used.
Finally, we can calculate the molar mass of the unknown acid by dividing the mass of the unknown acid by the moles of HA reacted.
Similarly, we can follow the same steps to calculate the molar mass for trials 2 and 3.
3. Average Molar Mass:
To obtain the average molar mass, add up the molar masses calculated in each trial and divide it by the number of trials.
By performing these calculations for each trial and calculating the average, you can determine the molar mass of the unknown acid.