Answer:
This question is incomplete. The completed question is below
Which expression represents the percent by mass of nitrogen in NH4NO3?
A) 14 g N/80 g NH₄ NO₃ ₓ 100%
B) 28 g N/80 g NH₄ NO₃ ₓ 100%
C) 80 g NH₄ NO₃ /14 g N ₓ 100%
D) 80 g NH₄ NO₃ /28 g N ₓ 100%
The correct option is B
Explanation:
To calculate the percentage by mass of nitrogen in the compound, the formula will be
total mass of nitrogen/total mass of compound × 100
Atomic mass of nitrogen (N) is 14 g/mol
There are 2 nitrogen atoms present in the compound as highlighted below
<u><em>Total mass of nitrogen</em></u> (N) present in NH₄ NO₃ = 14 × 2 = 28g
Atomic mass of hydrogen (H) is 1 g/mol. There are 4 hydrogen atoms present in the compound, NH₄NO₃.
Atomic mass of oxygen (O) is 16 g/mol. There are 3 oxygen atoms present in the compound, NH₄NO₃
<u><em>Total mass of the compound</em></u> =
(14 × 2) + (1 ×4) + (16 × 3) = 80g
Hence, the percentage by mass of nitrogen in the compound (as shown in the formula earlier) is
28g of N/80g of NH₄NO₃ × 100%
