A nitric acid solution of unknown concentration is used to titrate 0.771g of sodium tyrosinate (NaC9H10NO3). If the endpoint is reached when 32.79mL of nitric acid has been added, what is the concentration of the unknown nitric acid solution?
I assume this is a 1:1 reaction.
mols C compound = grams/molar mass
mols HNO3 = same
M HNO2 = mols HNO3/L HNO2
To find the concentration of the unknown nitric acid solution, we can use the concept of stoichiometry and the balanced equation of the reaction between nitric acid (HNO3) and sodium tyrosinate (NaC9H10NO3):
HNO3 + NaC9H10NO3 -> H2O + NaNO3 + C9H10NO3
In this reaction, 1 mole of nitric acid reacts with 1 mole of sodium tyrosinate.
First, we need to calculate the number of moles of sodium tyrosinate used in the titration. We can calculate the molar mass of sodium tyrosinate:
1 Na: 1 x 22.99 g/mol = 22.99 g/mol
9 C: 9 x 12.01 g/mol = 108.09 g/mol
10 H: 10 x 1.01 g/mol = 10.10 g/mol
1 N: 1 x 14.01 g/mol = 14.01 g/mol
3 O: 3 x 16.00 g/mol = 48.00 g/mol
Total molar mass: 202.19 g/mol
Now, we can calculate the number of moles of sodium tyrosinate used:
Number of moles = Mass / Molar mass = 0.771 g / 202.19 g/mol = 0.00381 mol
According to the balanced equation, the stoichiometry of the reaction is 1:1 between nitric acid and sodium tyrosinate. This means that the number of moles of nitric acid used is also 0.00381 mol.
Now, let's calculate the concentration of the unknown nitric acid solution. The volume of nitric acid added is given as 32.79 mL. Remember, we need to convert this to liters:
Volume of nitric acid = 32.79 mL = 32.79 mL x (1 L / 1000 mL) = 0.03279 L
Next, divide the number of moles of nitric acid by the volume of nitric acid added:
Concentration = Number of moles / Volume = 0.00381 mol / 0.03279 L
Now we have the concentration of the unknown nitric acid solution. Calculate the value using a calculator:
Concentration = 0.116 M (rounded to three decimal places)
Therefore, the concentration of the unknown nitric acid solution is approximately 0.116 M.