Consider equation:
` P_4O_10 + H_2O → H_3PO_4`.
Number of moles of `H_3PO_4` produced by reaction of 1 mole of `P_4O_10` is _________.

Answer

To determine the number of moles of H3PO4 produced by the reaction of 1 mole of P4O10, we need to balance the chemical equation given:

1. **Write the unbalanced equation**:
\[ P_4O_{10} + H_2O \rightarrow H_3PO_4 \]

2. **Count the number of atoms for each element**:
- On the left side (reactants):
- Phosphorus (P): 4 (from P4O10)
- Oxygen (O): 10 (from P4O10)
- Hydrogen (H): 2 (from H2O)
- On the right side (products):
- Phosphorus (P): 1 (from H3PO4)
- Oxygen (O): 4 (from H3PO4)
- Hydrogen (H): 3 (from H3PO4)

3. **Balance the phosphorus atoms**:
- Since there are 4 phosphorus atoms in P4O10 and only 1 in H3PO4, we need to place a coefficient of 4 in front of H3PO4:
\[ P_4O_{10} + H_2O \rightarrow 4 H_3PO_4 \]

4. **Recount the atoms after this change**:
- On the right side now:
- Phosphorus (P): 4 (from 4 H3PO4)
- Oxygen (O): 16 (4 H3PO4 × 4 O each)
- Hydrogen (H): 12 (4 H3PO4 × 3 H each)

5. **Balance the oxygen atoms**:
- Now we have 10 oxygen atoms from P4O10 and need to balance it with the water (H2O). We need to find how many H2O molecules are required to provide the additional oxygen:
- Total oxygen needed on the right side is 16, and we already have 10 from P4O10, so we need 6 more from H2O:
\[ P_4O_{10} + 6 H_2O \rightarrow 4 H_3PO_4 \]

6. **Recount the hydrogen atoms**:
- Now we have 6 H2O contributing 12 hydrogen atoms, which balances with the 12 hydrogen atoms in 4 H3PO4.

7. **Final balanced equation**:
\[ P_4O_{10} + 6 H_2O \rightarrow 4 H_3PO_4 \]

8. **Determine the number of moles of H3PO4 produced**:
- From the balanced equation, we see that 1 mole of P4O10 produces 4 moles of H3PO4.

Thus, the number of moles of H3PO4 produced by the reaction of 1 mole of P4O10 is **4 moles**.