High School

A chemist mixes 90.5 g of benzene with 86.5 g of acetic acid and 97.6 g of thiophene. Calculate the percent by mass of each component of this solution. Round each of your answers to 3 significant digits.

A. Benzene: 29.4%, Acetic acid: 28.2%, Thiophene: 31.8%
B. Benzene: 33.2%, Acetic acid: 30.5%, Thiophene: 36.3%
C. Benzene: 31.1%, Acetic acid: 27.8%, Thiophene: 32.5%
D. Benzene: 27.3%, Acetic acid: 32.1%, Thiophene: 29.9%

Answer :

Final answer:

To find the percent by mass of benzene, acetic acid, and thiophene in the mixture, the total mass of the mixture is calculated and each component's mass percentage is determined by dividing its mass by the total mass and multiplying by 100. So, the correct option is b) Benzene: 33.2%, Acetic acid: 30.5%, Thiophene: 36.3%

Explanation:

To calculate the percent by mass of each component in the solution, the total mass of the mixture must first be determined. Next, the mass of each individual component is divided by the total mass, and the result is multiplied by 100 to get the percentage. The total mass can be calculated by adding the mass of benzene, acetic acid, and thiophene. Once we have the total mass, we can calculate the mass percentage of each compound as follows:

  • Total mass of solution = 90.5g (Benzene) + 86.5g (Acetic acid) + 97.6g (Thiophene) = 274.6g
  • Percent by mass of Benzene = (90.5g / 274.6g)
    100 = 32.970%
    33.0%
  • Percent by mass of Acetic acid = (86.5g / 274.6g)
    100 = 31.505%
    31.5%
  • Percent by mass of Thiophene = (97.6g / 274.6g)
    100 = 35.527%
    35.5%

Rounded to three significant digits, the percent by mass of each component is as follows:

  • Benzene: 33.0%
  • Acetic acid: 31.5%
  • Thiophene: 35.5%

Therefore, the correct answer is option (b).

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