Calculate the percent by mass of each element in
ammonium nitrate (nh4no3).
the first step is to calculate the molar mass of
ammonium nitrate.
what elements are present in ammonium nitrate?

See below in bold.

Explanation:

Nitrogen, Hydrogen and Oxygen are the elements present in ammonium nitrate.

The Molar Mass =  2N + 4H  + 3 O

= 2*14.007 + 4*1.008 + 3*15.999

= 80.043.

Percentage of Nitrogen = (2 * 14.007) * 100 / 80.043

= 35.00 %.

Percentage of Hydrogen = (4* 1.008) * 100 / 80.043

= 5.04%.

Percentage of Oxygen = (3 * 15.999) * 100 / 80.043

= 59.96 %.

c. 75.7

i think that is the right