Phosphoric acid, H3PO4, has some important applications. It can be used to produce fertilizers and it is present in soft drinks. Phosphoric acid can be made from phosphorus in a two step process:

Reaction 1: P4 + 5 O2 --> P4O10
Reaction 2: P4H10 + 6H2O--> 4H3PO4

A synthesis yielded 229g of H3PO4. How many moles of H3PO4 were produced?

I figured that out but I need help with this one:


How many moles of P4 would be required to produce the number of moles of H3PO4 determined from the question above which the answer is 2.34 for above.

Use the coefficients in the balanced equations to convert any value to any other value. In this case,

2.34 mol H3PO4 x (1 mol P4O10/4 mol H3PO4) x (1 mol P4/1 mol P4O10). Note how the unit cancel. The P4O10 cancels, and the H3PO4 cancels to leave what you want that looks like this.
2.34 x 1/4 x 1 mol P4 = (2.34/4) mol P4. You wanted mols P4.

To find the number of moles of H3PO4 produced, we need to use the molar mass of H3PO4 and the mass of the H3PO4 obtained from the synthesis.

The molar mass of H3PO4 can be calculated by adding up the atomic masses of its constituent elements (H, P, and O).

H3PO4:
- Atomic mass of H = 1 g/mol
- Atomic mass of P = 31 g/mol
- Atomic mass of O = 16 g/mol
- Multiply the atomic mass of each element by the number of atoms present in the formula and sum them up.
(3 * 1) + (1 * 31) + (4 * 16) = 3 + 31 + 64 = 98 g/mol

Now, we can use the molar mass to calculate the number of moles of H3PO4 produced.

First, convert the given mass of H3PO4 (229g) to moles using the formula:

Number of moles = Mass of substance / Molar mass

Number of moles of H3PO4 = 229 g / 98 g/mol ≈ 2.33 mol

Therefore, approximately 2.33 moles of H3PO4 were produced in the synthesis.