Question

A multi-nutrient fertilizer contains several different nitrogen containing compounds. The fertilizer is 53.2% CH4N2O (urea), 24.1% KNO3 , and 11.8% (NH4)2HPO4 by mass. The remainder of the fertilizer consists of substances that do not contain nitrogen. How much fertilizer should someone apply to provide 2.20g N to a plant?

Answer 1

Answer:

7.19g of fertilizer are required to provide 2.20g of N to a plant

Explanation:

In 100g of fertilizer, the amount of nitrogen could be obtained as follows using the ratio of molar mass of nitrogen*atoms of nitrongen / molar mass of the molecule:

CH4N2O = 53.2g * (14g/mol*2 / 60.06g/mol) = 24.8gN

KNO3 = 24.1g * (14g/mol*1 / 101.10g/mol) = 3.3g N

(NH4)2HPO4 = 11.8g * (14g/mol*2 / 132.06g/mol) = 2.5g N

The mass of nitrogen in 100g of fertilizer is 24.8g + 3.3g + 2.5g = 30.6g N

That is: 30.6g N / 100g of fertilizer.

To obtain 2.20g of nitrogen are required:

2.20g N * (100g Fertilizer / 30.6g N) =

7.19g of fertilizer are required to provide 2.20g of N to a plant