Question

Mr. Ragusa is approached in his lab by one of his students named Hassan. Hassan had found a bottle of nitric acid that did not have a labeled molarity and wanted Mr. Ragusa to help him find it's molarity. Mr. Ragusa filled a buret to 4.85 mL with 0.30 M NaOH. Mr. Ragusa added 5 mL of the acid to a flask and added some phenolphthalein. Mr. Ragusa hit the titration spot on, and the final volume in the buret was 43.69 mL. What is the concentration of the Nitric Acid?

Round your answer to 2 decimal places. Include a unit in your answer. (ex: 1.2M)
HNO3 + NaOH --> NaNO3 + H2O

Answer 1

2.33M

Step-by-step explanation:

1. First, make sure the equation is balanced. In this case it would be HNO3+NaOH --> NaNO3 + H2O. (it is already balanced here.)

2. Find the initial volume, final volume, the volume of acid, volume of NaOH.

a. Initial Volume: 4.85 mL

b. Final Volume: 43.69

c. Acid (HNO3) Volume: 5 mL

d Volume NaOH: Initial V - Final V --> 43.69 mL - 4.85 mL = 38.84 mL NaOH

3. Find moles of NaOH reacted using the volume from D. Convert this volume into Liters. Multiply the volume of NaOH by molarity of NaOH given to you before. (.30 M NaOH)

a. x mol NaOH/ .03884 L = .30 mol NaOH/ 1 mol = .011652 mol NaOH

4. Now find the moles of acid. The acid given to you in the equation is HNO3. The .011652 mol NaOH is from the moles reacted that you just found. The moles on the right side would be the co-efficient in front of the elements in the equation. Since this equation does not have any coefficients (it's already balanced), it would just be 1.

a. .011652 mol NaOH/ x mol HNO3 = 1 mol NaOH/ 1 mol HNO3.

x = .011652 mol HNO3

5. Now find the concentration, also known as molarity. Divide the .011652 mol by the volume of acid you have been given (5 mL). Before using 5 mL, divide it by 1000 to get the Liter form.

a. .011652 mol HNO3/ .005 L = 2.3304 M HNO3

I hope you understand now. God bless!