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20.000 grams of an unknown blue-grey crystalline solid was found on a science lab bench. chemical analysis indicates that the substance contained 4.336 grams of oxygen, 1.628 grams of carbon and the rest of lead. using this information, answer the following questions:

User Myusuf
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Final answer:

The question requires the calculation of percent composition for elements in a compound, which falls under Chemistry for High School. It also touches upon the concepts of the law of definite proportions and the law of multiple proportions, which are fundamental to understanding chemical compound formation.

Step-by-step explanation:

The subject of the question involves the determination of the chemical composition of an unknown substance through chemical analysis. More specifically, it refers to calculating the percent composition of the elements within the substance. The first part of the question deals with a blue-grey crystalline solid that contains oxygen, carbon, and lead. To find the percent composition, we would divide the mass of each element by the total mass of the sample and then multiply by 100 to get a percentage.

Looking at the given problem for the gaseous compound containing carbon, oxygen, and chlorine, the student is asked to calculate the percent composition of each element within the compound. The percent composition is given by the mass of the specific element divided by the total mass of the compound and then multiplied by 100.

In the context of the law of multiple proportions and law of definite proportions, these laws refer to the way elements combine to form compounds. The law of definite proportions states that a chemical compound always contains exactly the same proportion of elements by mass. The law of multiple proportions states that when elements combine, they do so in the ratio of small whole numbers (assuming they have the same type of chemical bonds).

To summarize, to determine the percent composition of a compound, one must know the masses of the individual components. From there, you calculate the percentages based on the total mass of the compound.

User Elnygren
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Final answer:

To calculate the percent composition by mass, divide the mass of each element by the total mass of the compound and multiply by 100. The elemental composition of the blue-grey crystalline solid is 21.68% oxygen, 8.14% carbon, and 70.18% lead.

Step-by-step explanation:

To determine the percent composition by mass for each element present in the blue-grey crystalline solid, you need to divide the mass of each element by the total mass of the compound, and then multiply by 100 to get a percentage. The given weights are 4.336 grams of oxygen (O), 1.628 grams of carbon (C), and the rest of the weight is attributed to lead (Pb). The initial given total mass of the compound is 20.000 grams.

  • Mass of Pb = total mass - (mass of O + mass of C) = 20.000 g - (4.336 g + 1.628 g) = 14.036 g
  • Percent composition of O = (4.336 g / 20.000 g) × 100% = 21.68%
  • Percent composition of C = (1.628 g / 20.000 g) × 100% = 8.14%
  • Percent composition of Pb = (14.036 g / 20.000 g) × 100% = 70.18%

Therefore, the blue-grey crystalline solid is composed of 21.68% oxygen, 8.14% carbon, and 70.18% lead by mass.

Complete question:

20.000 grams of an unknown blue-grey crystalline solid was found on a science lab bench. chemical analysis indicates that the substance contained 4.336 grams of oxygen, 1.628 grams of carbon and the rest of lead. using this information, answer the following questions:

Determine the percent composition by mass for each element present in the blue-grey crystalline solid.

User Circey
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