Question

PLEASE ANSWER QUICKLY!

Answer 1

Answer:

c

c

Explanation:

$h3po4 + 12.81 - p40.10$

Answer 2

Answer:

A. 837 grams of $H_3PO_4$ are produced when 12.81 moles of water react with an excess of $P_4O_{10}$

Explanation:

The balanced chemical equation is

$P_4 O_10 + 6 H_2 O > 4 H_3 PO_4$

Mole ratio of $H_2 O:H_3 PO_4$ is 6 : 4 or 3 : 2

As per the Equation

6 moles of water produces 4 moles of Phosphoric acid

So let us convert  

12.81 moles $H_2 O$ to moles $H_3 PO_4$ by using mole ratio and then to mass $H_3 PO_4$ by  multiplying with molar mass $H_3 PO_4$

$12.82 mol H_2 O \times \frac {(4mol H_3 PO_4)}{(6molH_2 O)} \times \frac {(98gH_3 PO_4)}{(1mol H_3 PO_4 )}$

$=837g H_3 PO_4$ is produced

Please note:  

Molar mass is the mass of 1 mole of the substance and its unit is g/mol

We find the molar mass by adding the atomic mass of the atoms present in it.

For example $H_3 PO_4$ contains 3 atoms of H, 1 atom of P and 4 atoms of O

So the molar mass

$=(3\times1.008)+(31\times1)+(4\times16)=98 g/mol$