Question

Найдите молекулярную формулу вещества , содержавшего по массе 82,8 % углерода и 17,2% водорода

Answer 1

У меня вышел ответ - C₄H₁₀

Answer 2

Molecular Formula Calculation

To find the molecular formula of a substance based on its percentage composition, we need to determine the empirical formula first. The empirical formula represents the simplest whole number ratio of atoms in a compound.

Given that the substance contains 82.8% carbon and 17.2% hydrogen, we can assume a 100g sample of the substance. This means we have 82.8g of carbon and 17.2g of hydrogen.

To calculate the empirical formula, we need to convert the mass of each element to moles. We can do this by dividing the mass of each element by its molar mass.

The molar mass of carbon (C) is approximately 12.01 g/mol, and the molar mass of hydrogen (H) is approximately 1.01 g/mol.

Calculating the number of moles for each element:

- Carbon (C): 82.8g / 12.01 g/mol = 6.89 mol - Hydrogen (H): 17.2g / 1.01 g/mol = 17.03 mol

Next, we need to find the simplest whole number ratio of moles between carbon and hydrogen. We can do this by dividing both values by the smallest number of moles (in this case, 6.89 mol).

- Carbon (C): 6.89 mol / 6.89 mol = 1 - Hydrogen (H): 17.03 mol / 6.89 mol ≈ 2.47

Rounding the ratio to the nearest whole number, we get approximately 1 carbon atom and 2 hydrogen atoms.

Therefore, the empirical formula of the substance is CH2.

Conclusion

The molecular formula of the substance containing approximately 82.8% carbon and 17.2% hydrogen is CH2.