A farmer supplies 1250.0 kg of a fertilizer that contains 10& nitrogen to his fields each year. Fifteen percent of the fertilizer washes into a river that runs through the farm. If the river flows at an average rate of 0.165 cubic feet per second, what is the additional concentration of nitrogen (expressed in milligrams of nitrogen per litter) in the river water due to the farmer's fertilizer?
kg N washed away is 1250 kg x 0.1 x 0.15 = ? kg.
That x 1E6 is mg N.
0.165 ft^2/s = 4.7 L/s (by the way that's liter and not litter; it's a volume not a litter of puppies).
concn = mg/4.7 for concn after 1 s but I'm unsure of the time involved. It seems to me that the value is different if you measure the amount of water after 1 s, 2s, 3s, etc.
To find the additional concentration of nitrogen in the river water due to the farmer's fertilizer, we need to follow these steps:
Step 1: Calculate the amount of nitrogen in the fertilizer that washes into the river.
The fertilizer contains 10% nitrogen, so the amount of nitrogen washed into the river is 10% of 1250.0 kg:
Nitrogen in the fertilizer = 10% of 1250.0 kg = (10/100) * 1250.0 kg = 125 kg.
Step 2: Calculate the amount of nitrogen that is contributed to the river per second.
Since 15% of the fertilizer washes into the river, we need to find how much nitrogen is contributed per second:
Nitrogen contributed per second = 15% of nitrogen in the fertilizer = (15/100) * 125 kg = 18.75 kg.
Step 3: Convert the amount of nitrogen contributed per second to milligrams.
As the question asks for the concentration of nitrogen in milligrams per liter, we need to convert the nitrogen amount from kilograms to milligrams:
1 kg = 1,000,000 milligrams.
So, the nitrogen contributed per second in milligrams = 18.75 kg * 1,000,000 mg/kg = 18,750,000 mg.
Step 4: Calculate the volume of water flowing through the river per second.
The river flows at an average rate of 0.165 cubic feet per second. To convert this to liters, we need to multiply by the conversion factor:
1 cubic foot = 28.3168 liters.
So, the volume of water flowing through the river per second = 0.165 cubic feet * 28.3168 liters/cubic foot = 4.67398 liters.
Step 5: Calculate the additional concentration of nitrogen in the river water.
The additional concentration of nitrogen in the river water is the ratio of nitrogen contributed per second to the volume of water flowing per second:
Additional concentration of nitrogen = Nitrogen contributed per second / Volume of water flowing per second.
Substituting the values:
Additional concentration of nitrogen = 18,750,000 mg / 4.67398 liters.
Calculating the value:
Additional concentration of nitrogen = 4,006,968.21 milligrams per liter.
Hence, the additional concentration of nitrogen in the river water due to the farmer's fertilizer is approximately 4,006,968.21 milligrams per liter.