Question

При полном сгорании вещ-ва массой 1,1 г, получено 2,2 г CO2 и 0,90 г воды. Известно, что 0,7 дм3 паров вещ-ва имеют массу 2,75 г. Найдите молекулярную формулу вещества.

Answer 1

Calculation of the Molecular Formula

To find the molecular formula of the substance, we need to calculate the number of moles of carbon and hydrogen in the given mass of carbon dioxide (CO2) and water (H2O).

Given: - Mass of CO2 = 2.2 g - Mass of H2O = 0.90 g - Mass of substance in 0.7 dm3 of vapor = 2.75 g

First, let's calculate the number of moles of carbon and oxygen in CO2: - Molar mass of carbon (C) = 12.01 g/mol - Molar mass of oxygen (O) = 16.00 g/mol

Number of moles of carbon in CO2 = Mass of carbon in CO2 / Molar mass of carbon Number of moles of oxygen in CO2 = Mass of oxygen in CO2 / Molar mass of oxygen

Next, let's calculate the number of moles of hydrogen and oxygen in H2O: - Molar mass of hydrogen (H) = 1.01 g/mol - Molar mass of oxygen (O) = 16.00 g/mol

Number of moles of hydrogen in H2O = Mass of hydrogen in H2O / Molar mass of hydrogen Number of moles of oxygen in H2O = Mass of oxygen in H2O / Molar mass of oxygen

Finally, let's calculate the number of moles of carbon and hydrogen in the given mass of the substance: - Mass of substance = Mass of carbon + Mass of hydrogen

Number of moles of carbon in the substance = Mass of carbon in the substance / Molar mass of carbon Number of moles of hydrogen in the substance = Mass of hydrogen in the substance / Molar mass of hydrogen

Now, we can determine the molecular formula of the substance by comparing the ratios of the number of moles of carbon, hydrogen, and oxygen in CO2 and H2O to the number of moles of carbon and hydrogen in the substance.

Please note that the search results provided by You.com do not contain the necessary information to directly answer this question. Therefore, we will proceed with the calculation based on the given information.

Let's calculate the number of moles of carbon and oxygen in CO2: - Mass of carbon in CO2 = 2.2 g - Molar mass of carbon = 12.01 g/mol - Number of moles of carbon in CO2 = 2.2 g / 12.01 g/mol

Number of moles of carbon in CO2 = 0.183 moles

Since CO2 has one carbon atom, the number of moles of carbon in the substance is also 0.183 moles.

Next, let's calculate the number of moles of hydrogen and oxygen in H2O: - Mass of hydrogen in H2O = 0.90 g - Molar mass of hydrogen = 1.01 g/mol - Number of moles of hydrogen in H2O = 0.90 g / 1.01 g/mol

Number of moles of hydrogen in H2O = 0.891 moles

Since H2O has two hydrogen atoms, the number of moles of hydrogen in the substance is 2 * 0.891 moles = 1.782 moles.

Now, let's calculate the number of moles of carbon and hydrogen in the substance: - Mass of the substance = 2.75 g - Number of moles of carbon in the substance = 0.183 moles - Number of moles of hydrogen in the substance = 1.782 moles

The molecular formula of the substance can be determined by comparing the ratios of the number of moles of carbon and hydrogen in the substance to the number of moles of carbon and hydrogen in CO2 and H2O.

Based on the given information, the molecular formula of the substance cannot be determined. Additional information is needed to calculate the molecular formula accurately.

Please provide more information if available, or let me know if there is anything else I can help you with.