Calculate the percentage by mass of oxygen in the following compounds: (e) dioxin, C₁₂H₄Cl₄O₂

Verified step by step guidance

1. Identify the molar mass of each element in the compound. For dioxin (C12H4Cl4O2), the elements are carbon (C), hydrogen (H), chlorine (Cl), and oxygen (O). The atomic masses are approximately: Carbon = 12.01 g/mol, Hydrogen = 1.01 g/mol, Chlorine = 35.45 g/mol, Oxygen = 16.00 g/mol.
2. Calculate the molar mass of the compound by multiplying the atomic mass of each element by the number of atoms of that element in the formula and then summing these values. For dioxin, this would be: (12.01 g/mol * 12) + (1.01 g/mol * 4) + (35.45 g/mol * 4) + (16.00 g/mol * 2).
3. Calculate the total mass of oxygen in the compound by multiplying the atomic mass of oxygen by the number of oxygen atoms in the formula: 16.00 g/mol * 2.
4. Determine the percentage by mass of oxygen in the compound using the formula: (mass of oxygen / molar mass of compound) * 100%.
5. This percentage represents the mass fraction of oxygen in dioxin, expressed as a percentage.

Key Concepts

Molar Mass Calculation

Molar mass is the mass of one mole of a substance, calculated by summing the atomic masses of all atoms in its chemical formula. For dioxin (C12H4Cl4O2), you would multiply the number of each type of atom by its respective atomic mass from the periodic table and then add these values together to find the total molar mass.

Percentage by Mass

Percentage by mass is a way to express the concentration of a component in a compound. It is calculated by dividing the mass of the component (in this case, oxygen) by the total molar mass of the compound, then multiplying by 100 to convert it to a percentage. This helps in understanding the composition of the compound.

Chemical Composition

Chemical composition refers to the types and amounts of elements that make up a compound. In dioxin, the presence of carbon, hydrogen, chlorine, and oxygen indicates its structure and properties. Understanding the composition is essential for calculating the mass percentage of specific elements, such as oxygen, in the compound.