Question

Массовая доля водорода в углеводороде равна 14,29%, а его относительная плотность по азоту равна 2.1)Определите молекулярную формулу углеводорова2)Какой объем воздуха при Н.У потребуется для сгораяния 56г данного соединения?

Answer 1

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Answer 2

Mass fraction of hydrogen in the hydrocarbon:

The mass fraction of hydrogen in the hydrocarbon is given as 14.29%. This means that for every 100 grams of the hydrocarbon, 14.29 grams are hydrogen. [[1]]

Relative density of the hydrocarbon:

The relative density of the hydrocarbon with respect to nitrogen is given as 2.1. Relative density is the ratio of the density of a substance to the density of a reference substance, in this case, nitrogen. [[1]]

Determining the molecular formula of the hydrocarbon:

To determine the molecular formula of the hydrocarbon, we need to know the molar mass of the compound. The molar mass is the mass of one mole of the substance. Since we are given the mass fraction of hydrogen, we can assume that the hydrocarbon contains only carbon and hydrogen.

To find the molecular formula, we can follow these steps: 1. Calculate the mass of carbon in the hydrocarbon: - Since the mass fraction of hydrogen is 14.29%, the mass fraction of carbon can be calculated as 100% - 14.29% = 85.71%. - Let's assume we have 100 grams of the hydrocarbon. Therefore, the mass of carbon is 85.71 grams.

2. Calculate the number of moles of carbon: - The molar mass of carbon is approximately 12.01 g/mol. - The number of moles of carbon can be calculated using the formula: moles = mass / molar mass. - Therefore, the number of moles of carbon is 85.71 g / 12.01 g/mol = 7.14 mol.

3. Calculate the number of moles of hydrogen: - The molar mass of hydrogen is approximately 1.01 g/mol. - The number of moles of hydrogen can be calculated using the formula: moles = mass / molar mass. - Since we know the mass fraction of hydrogen is 14.29%, we can calculate the mass of hydrogen as 14.29% of 100 grams = 14.29 grams. - Therefore, the number of moles of hydrogen is 14.29 g / 1.01 g/mol = 14.15 mol.

4. Find the ratio of moles of carbon to moles of hydrogen: - Divide the number of moles of carbon by the number of moles of hydrogen. - The ratio is 7.14 mol / 14.15 mol, which simplifies to approximately 0.504.

5. Determine the empirical formula: - The empirical formula represents the simplest whole number ratio of atoms in a compound. - Since the ratio of moles of carbon to moles of hydrogen is approximately 0.504, the empirical formula can be written as CH2.

6. Determine the molecular formula: - The molecular formula represents the actual number of atoms of each element in a compound. - To find the molecular formula, we need to know the molar mass of the compound. - Without the molar mass, we cannot determine the molecular formula with certainty.

Therefore, without the molar mass of the compound, we cannot determine the molecular formula of the hydrocarbon.