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Many modern antiseptics are based on phenol - Scottish Highers Chemistry - Question 12 - 2018
Question 12
Many modern antiseptics are based on phenol. The table shows the germ-killing power of some phenol compounds. (a) | Compound | Structure | Germ-killing... show full transcript
Worked Solution & Example Answer:Many modern antiseptics are based on phenol - Scottish Highers Chemistry - Question 12 - 2018
Step 1
Suggest two ways in which structural features increase germ-killing power of phenol compounds.
Answer
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The introduction of more chlorine atoms can enhance germicidal activity due to the electronegative nature of chlorine, which increases the overall reactivity of the molecule.
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Adding alkyl groups, such as larger or branched hydrocarbons, can improve the solubility and efficacy of the phenol compound, facilitating better interaction with microbial cells.
Step 2
Step 3
Calculate the mass of phenol, in kg, produced from 117 kg of benzene if the percentage yield is 90%.
Answer
First, we determine the theoretical yield of phenol from benzene using the reaction stoichiometry:
- The molar mass of benzene (C6H6) is 78.0 g.
- The molar mass of phenol (C6H5OH) is 94.0 g.
Using the conversion, for 117 kg of benzene:
ext{Number of moles of benzene} = rac{117,000 g}{78.0 g/mol} ext{ = 1,500 mol}
Since the reaction shows a 1:1 molar ratio:
Theoretical moles of phenol produced = 1,500 mol.
Theoretical mass of phenol = 1,500 mol * 94.0 g/mol = 141,000 g.
Taking into account the percentage yield of 90%:
Mass of phenol produced = 0.90 * 141,000 g = 126,900 g = 126.9 kg.
Step 4