Question #8148d

Feb 20, 2017

The absorbed heat is 15.0 kJ.

Explanation:

The main reaction takes the following form:

$\text{NH"_4"NO"_3"(s)" rarr "NH"_4^"+""(aq)" + "NO"_3^"-""(aq)"color(white)(mmmmm)"(1)}$

It is well known that, for any material, the relationship between the number of moles, the mass of material (grams) and the molar mass follows the form below:

$\text{Number of Moles" = "Mass of Material (grams)"/"Molar Mass}$

The molar mass of

$\text{NH"_4"NO"_3 = "[14.01 + 4(1.01) + 14.01 +3(16.00)] g/mol" = "80.06 g/mol}$

Therefore, in 40.0 g of ${\text{NH"_4"NO}}_{3}$, there are

$\text{40.0 g"/"80.06 g/mol}$ or $\text{0.4996 mol}$

Thus, $\text{absorbed heat" = "0.4996 mol" xx "30.0 kJ/mol" = "15.0 kJ}$

With kind regards
Dr. Mamdouh Younes