Answer:
3.11 mol/kg
Explanation:
Molality M = number of moles of solute, n/mass of solvent, m
To calculate the number of moles of glycerol (C₃H₈O₃) in 22.75 g of glycerol, we find its molar (molecular) mass, M',
So, M' = 3 × atomic mass of carbon + 8 × atomic mass hydrogen + 3 × atomic mass of oxygen
= 3 × 12 g/mol + 8 × 1 g/mol + 3 × 16 g/mol = 36 g/mol + 8 g/mol + 48 g/mol = 92 g/mol.
So, number of moles of glycerol, n = m'/M' where m' = mass of glycerol = 22.75 g and M' = molecular mass of glycerol = 92 g/mol
So, n = m'/M'
n = 22.75 g/92 g/mol
n = 0.247 mol
So, the molality of the solution M = n/m
Since m = mass of ethanol = 79.6 g = 0.0796 kg, substituting the value of n into the equation, we have
M = 0.247 mol/0.0796 kg
M = 3.11 mol/kg
So, the molality of the solution is 3.11 mol/kg.
The presence of a large population of sludgeworms indicates water depleted of oxygen and a high level of organic pollution.
The sludgeworms Tubifex is harvested and sold as tropical fish food since it is common near sewer outlets and serves as a sign of water or organic pollution. Polychaetes are crucial in rearranging the silt on the ocean floor.
Organic contamination happens when too much organic material, such sewage or manure, gets into the water.
There will be more decomposers and sludgeworms in a pond as the organic content accumulates. These decomposers and sludgeworms develop quickly and consume a lot of oxygen as they do so.
Hence, Sludgeworms are a sign of an abundance of oxygen-depleted water and significant levels of organic pollutants.
Learn more about Water pollution here brainly.com/question/1235358
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<span>1. Made of cells.
2. Sense and Respond to Change.
3. Reproduction.
4. DNA.
5. Use Energy.
<span>6. Grow and Develop</span></span>
