Question

1. use a funnel to fill a clean buret to the 25 ml mark with 0.100 m naoh (sodium hydroxide)
2. place the buret in a buret clamp on the buret stand.
3. record the concentration of the naoh (0.100 m naoh) in the data table.
4. record the initial level of naoh that is in the buret in the data table.
5. place the erlenmeyer flask in the space below the buret so that the naoh can be added.
6. begin the titration by slowly opening the stopcock on the buret so that the naoh is added at a rate of one drop per second. as you titrate, make sure to swirl the flask to stir the contents.
7. continue the titration until the solutions turns a permanent faint pink color and then stop the titration by closing the stopcock on the buret.
8. record the final level of naoh that is in the buret in the data table.
9. if instructed to do a second trial, repeat steps 1 through 13 and record the data in the appropriate places for trial 2 in the data table.

data table

mass of unknown acid (grams)	trial 1	trial 2
concentration of base (naoh)	0.100m
initial level of naoh	25ml
final level of naoh	45.6ml
volume of base used	20.6ml

|molar mass of unknown acid|
|average molar mass of unknown acid|
data analysis

1. we will first find the number of moles of base (naoh) used to neutralize the unknown acid by using the molarity equation: molarity = moles of base / volume of base used (l)

Explanation:

Step1: Convert volume of base to liters

The volume of base used is $20.6\ mL$. To use in the molarity - moles formula, we convert it to liters. $V = 20.6\ mL\times\frac{1\ L}{1000\ mL}=0.0206\ L$.

Step2: Calculate moles of base

The molarity of $NaOH$ is $M = 0.100\ M$. Using the formula $M=\frac{n}{V}$ (where $n$ is moles and $V$ is volume in liters), we can find the moles of $NaOH$. Rearranging for $n$, we get $n = M\times V$. Substituting the values, $n = 0.100\ mol/L\times0.0206\ L = 0.00206\ mol$.

Step3: Assume 1:1 mole - ratio (for monoprotic acid)

Assuming the acid is monoprotic, the moles of acid is equal to the moles of base at the equivalence - point. So, moles of acid $n_{acid}=0.00206\ mol$.

Step4: Calculate molar mass of acid

The mass of the unknown acid is $m = 0.45\ g$. The molar mass $M_{acid}=\frac{m}{n_{acid}}$. Substituting the values, $M_{acid}=\frac{0.45\ g}{0.00206\ mol}\approx218.45\ g/mol$.

Answer:

The molar mass of the unknown acid is approximately $218.45\ g/mol$.