Question #8148d

1 Answer
Dr. Mamdouh Younes · Ernest Z. · Stefan V.
Feb 20, 2017

The absorbed heat is 15.0 kJ.

Explanation:

The main reaction takes the following form:

#"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:

#"Number of Moles" = "Mass of Material (grams)"/"Molar Mass"#

The molar mass of

#"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 #"NH"_4"NO"_3#, there are

#"40.0 g"/"80.06 g/mol"# or #"0.4996 mol"#

Thus, #"absorbed heat" = "0.4996 mol" xx "30.0 kJ/mol" = "15.0 kJ"#

With kind regards
Dr. Mamdouh Younes

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