# Many grams of H_3PO_4 are produced when 12.0 moles of water react with an excess of P_4O_10? P_4O_10(s) + 6H_2O(l) -> 4H_3PO_4(aq)?

Apr 30, 2017

You have the stoichiometric equation..........

#### Explanation:

And, by the stoichiometry, if $\text{12 mole}$ of water react, then $\text{8 mole}$ of $\text{phosphoric acid}$ will result, and this constitutes a mass of.............

$12 \cdot m o l \times 97.99 \cdot g \cdot m o {l}^{-} 1 \cong 1200 \cdot g$

When you use ${P}_{4} {O}_{10}$ in the lab (and it is often used as a dessicant), usually when you take the lid off a pre-used jar, you will often notice a syrupy crust of phosphoric acid on top of the powder. You have to dig down beneath this crust to get to the free-flowing powder.

Of what do you think the syrupy crust is composed?