A sample of fertiliser was analysed and found to contain 80% by mass of ammonium nitrate (NH₄NO₃) and 20% by mass of potassium chloride (KCl) - VCE - SSCE Chemistry - Question 8 - 2004 - Paper 1
Question 8
A sample of fertiliser was analysed and found to contain 80% by mass of ammonium nitrate (NH₄NO₃) and 20% by mass of potassium chloride (KCl).
The mass of nitrogen ... show full transcript
Worked Solution & Example Answer:A sample of fertiliser was analysed and found to contain 80% by mass of ammonium nitrate (NH₄NO₃) and 20% by mass of potassium chloride (KCl) - VCE - SSCE Chemistry - Question 8 - 2004 - Paper 1
Step 1
Calculate the mass of ammonium nitrate (NH₄NO₃)
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The total mass of the fertiliser packet is 1.00 kg. Since it contains 80% ammonium nitrate, the mass of ammonium nitrate is:
1.00extkgimes0.80=0.80extkg=800extg
Step 2
Determine the mass of nitrogen in ammonium nitrate (NH₄NO₃)
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The molecular formula of ammonium nitrate is NH₄NO₃. The molar mass of nitrogen (N) in NH₄NO₃ is combined from 2 nitrogen atoms:
Molar mass of N = 14 g/mol
There are 2 nitrogen atoms in the formula, therefore:
2imes14extg/mol=28extg/mol
The mass of nitrogen in the ammonium nitrate can be calculated as follows:
ext{Mass of N in NH₄NO₃} = rac{28 ext{ g/mol}}{80 ext{ g/mol (NH₄NO₃)}} imes 800 ext{ g} = 280 ext{ g}
Step 3
Final answer for the mass of nitrogen in the fertiliser
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The mass of nitrogen in a 1.00 kg packet of the fertiliser is 280 g. Therefore, the correct option is: C. 280 g.
