A solution containing 83.100 g of sodium hydroxide [molar mass = 40.0 g/mol] was neutralised using phosphoric acid.
Calculate the moles of sodium phosphate formed (assuming that the reaction goes to completion). Give your answer to three significant figures.
I'm not sure the steps required
3NaOH + H3PO4 ==> Na3PO4 + 3H2O
mols NaOH = grams/molar mass = ?
Using the coefficients in the balanced equation, convert mols NaOH to mols Na3PO4. That's ?mols NaOH x (1 mol Na3PO4/3 mols NaOH) = ? mols NaOH x 1/3 = ? mols Na3PO4.
Steps for solving stoichiometry problem.
1. Write and balance the equation.
2. Convert what you have to mols.
3. Using the coefficients in the balanced equation, convert mols of what you have to mols of what you want.
4. Convert mols of what you want to whatever unit you want; ie. if grams then g = mols x molar mass. If volume the mols x 22.4 L/mol
To calculate the moles of sodium phosphate formed, you will need to follow a few steps:
1. Determine the balanced equation for the reaction between sodium hydroxide and phosphoric acid. This will give you the stoichiometry of the reaction.
The balanced equation for the reaction is:
3NaOH + H3PO4 → Na3PO4 + 3H2O
2. Calculate the molecular weight of sodium phosphate (Na3PO4).
The molecular weight of Na3PO4 is calculated by adding up the atomic masses of each element:
Na: 22.99 g/mol × 3 = 68.97 g/mol
P: 30.97 g/mol
O: 16.00 g/mol × 4 = 64.00 g/mol
Total molecular weight of Na3PO4 = 68.97 g/mol + 30.97 g/mol + 64.00 g/mol = 163.94 g/mol
3. Convert the mass of sodium hydroxide given in grams to moles.
Moles = mass / molar mass
Moles of NaOH = 83.100 g / 40.0 g/mol ≈ 2.08 mol
4. Use the stoichiometry from the balanced equation to determine the mole ratio between sodium hydroxide and sodium phosphate.
From the balanced equation, we can see that the mole ratio between NaOH and Na3PO4 is 3:1. This means that for every 3 moles of NaOH, 1 mole of Na3PO4 is formed.
5. Calculate the moles of sodium phosphate formed.
Moles of Na3PO4 = Moles of NaOH / 3
Moles of Na3PO4 ≈ 2.08 mol / 3 ≈ 0.693 mol
Therefore, the moles of sodium phosphate formed, assuming the reaction goes to completion, is approximately 0.693 mol.