Cola contains H3PO4. In order to determine the concentration of phosphoric acid in 50.0 mL of cola, a precipitation reaction with excess silver nitrate was carried out. The product, silver phosphate, was dried and found to weigh 0.0576g. What is the concentration of phosphoric acid in the cola?
To determine the concentration of phosphoric acid in the cola, we need to use stoichiometry and the mass of the precipitated silver phosphate.
Here's how you can calculate the concentration of phosphoric acid step by step:
1. Write the balanced equation for the reaction:
H3PO4 + 3AgNO3 -> Ag3PO4 + 3HNO3
2. Calculate the molar mass of silver phosphate (Ag3PO4):
Ag: 1 × 107.87 g/mol = 107.87 g/mol
P: 1 × 30.97 g/mol = 30.97 g/mol
O: 4 × 16.00 g/mol = 64.00 g/mol
Molar mass of Ag3PO4 = 107.87 + 30.97 + 64.00 = 202.84 g/mol
3. Calculate the number of moles of silver phosphate using its mass and molar mass:
Moles of Ag3PO4 = Mass of Ag3PO4 / Molar mass of Ag3PO4
= 0.0576 g / 202.84 g/mol
4. Determine the molar ratio of H3PO4 to Ag3PO4 from the balanced equation:
From the equation, 1 mole of H3PO4 reacts with 1 mole of Ag3PO4.
5. Calculate the moles of H3PO4:
Moles of H3PO4 = Moles of Ag3PO4
6. Convert the moles of H3PO4 to concentration in the given volume:
Volume of cola = 50.0 mL = 0.0500 L
Concentration (molarity) of H3PO4 = Moles of H3PO4 / Volume of cola
Now, substitute the known values into the equation:
Moles of H3PO4 = 0.0576 g / 202.84 g/mol
= 0.000283 mol
Volume of cola = 0.0500 L
Concentration of H3PO4 = 0.000283 mol / 0.0500 L
So, the concentration of phosphoric acid in the cola is approximately 0.00566 M.
To determine the concentration of phosphoric acid in the cola, we can start by writing the balanced equation for the reaction between silver nitrate (AgNO3) and phosphoric acid (H3PO4):
3AgNO3 + H3PO4 -> Ag3PO4 + 3HNO3
From the equation, we can see that the ratio between AgNO3 and H3PO4 is 3:1. This means that each mole of Ag3PO4 (silver phosphate) corresponds to 1/3 mole of H3PO4.
To find the number of moles of Ag3PO4 produced, we need to convert the mass of Ag3PO4 to moles using its molar mass. The molar mass of Ag3PO4 is calculated by adding the atomic masses of silver (Ag) and phosphate (PO4).
Molar mass of Ag3PO4:
(3x Ag) + (PO4) = (3x 107.87 g/mol) + 94.97 g/mol = 331.58 g/mol
Next, we can calculate the number of moles of Ag3PO4:
moles = mass / molar mass
moles = 0.0576 g / 331.58 g/mol
Now, since each mole of Ag3PO4 corresponds to 1/3 mole of H3PO4, we can calculate the number of moles of H3PO4:
moles of H3PO4 = moles of Ag3PO4 x (1/3)
Finally, to determine the concentration of phosphoric acid in the cola, we divide the number of moles of H3PO4 by the volume of the cola sample in liters:
concentration (in mol/L) = moles of H3PO4 / volume (in L)
Since the volume of the cola sample is given in milliliters (mL), we need to convert it to liters by dividing by 1000:
volume (in L) = 50.0 mL / 1000 = 0.0500 L
Now we can calculate the concentration of phosphoric acid in the cola:
concentration (in mol/L) = moles of H3PO4 / volume (in L)
0.0576 g Ag3PO4 = how many moles.
moles = g/molar mass.
1 mol Ag3PO4 contains how many moles of PO4^-3?
1 mol PO4^-3 is equivalent to how many H3PO4 moles?
Convert moles H3PO4 to grams and divide by 50 mL to obtain g H3PO4/mL or multiply that by 100 to convert to %.