A sausage sample was found to contain 65% moisture, based on fresh weight. The sausage was dried in an oven until its moisture content was 10%. A 2.0 g portion of the dried sausage was extracted with the Soxhlet method to determine the amount of crude fat. A clean Soxhlet flask weighed 115.0 g. After refluxing for 3 hours using petroleum ether, the solvent was removed by evaporation on the hot plate then completely dried in an oven. The cooled flask was reweighed and gave a weight of 116.5g. Calculate the percentage crude fat in the original sausage (wet weight basis)

Question

A sausage sample was found to contain 65% moisture, based on fresh weight. The sausage was dried in an oven until its moisture content was 10%. A 2.0 g portion of the dried sausage was extracted with the Soxhlet method to determine the amount of crude fat. A clean Soxhlet flask weighed 115.0 g. After refluxing for 3 hours using petroleum ether, the solvent was removed by evaporation on the hot plate then completely dried in an oven. The cooled flask was reweighed and gave a weight of 116.5g. Calculate the percentage crude fat in the original sausage (wet weight basis)

I've calculated 75% crude fat in dry weight (10%moisture) but how do I convert that into the wet weight (65% moisture)

Answer 1

consider that the amount of sausage never changed.

did the solvent remove the fat?

Answer 2

To convert the percentage of crude fat in the dry weight to the wet weight basis, you need to account for the moisture content in the original sausage.

Here's how you can do it:

Step 1: Calculate the dry weight of the sausage.
Given that a 2.0 g portion of the dried sausage was extracted, and the Soxhlet flask weighed 115.0 g before the extraction, we can determine the weight of the dried sausage as:
Dried sausage weight = Flask weight after extraction - Flask weight before extraction
Dried sausage weight = 116.5 g - 115.0 g = 1.5 g

Step 2: Calculate the original wet weight of the sausage.
Since the moisture content in the original sausage is 65%, we can determine the wet weight using the formula:
Wet weight = Dry weight / (1 - Moisture content)
Wet weight = 1.5 g / (1 - 0.65) = 4.29 g

Step 3: Calculate the percentage of crude fat in the original sausage (wet weight basis).
Now that we have the wet weight of the sausage, divide the weight of the crude fat in the dried sausage (which is 75% of the dry weight) by the wet weight of the sausage and multiply by 100 to get the percentage:
Percentage crude fat in wet weight = (Crude fat in dry weight / Dry weight) * 100
Percentage crude fat in wet weight = (0.75 * 1.5 g / 1.5 g) * 100 = 75%

Therefore, the percentage of crude fat in the original sausage, on a wet weight basis, is 75%.