Question

ДАМ 40 БАЛЛОВ СРОЧНО 9. Унаслідок спалювання вуглеводню масою 6 г одержали карбон(IV) оксид об'ємом 8,96 л (н.у.) та воду масою 10,8 г. Вiдносна густина вугле- водню за воднем - 15. Виведіть молекулярну формулу сполуки. - Розв’язання​

Answer 1

To find the molecular formula of the compound, we need to determine the empirical formula first. The empirical formula gives the simplest whole number ratio of atoms in a compound.

Given: - Mass of carbon dioxide (CO2) = 6 g - Volume of carbon dioxide (CO2) = 8.96 L (at standard temperature and pressure) - Mass of water (H2O) = 10.8 g - Relative density of hydrogen to water = -15

Calculating the moles of carbon dioxide (CO2):

To calculate the moles of carbon dioxide, we can use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.

Since the volume is given at standard temperature and pressure (STP), we can use the values for STP: - Pressure (P) = 1 atm - Temperature (T) = 273 K

Using the ideal gas law equation, we can calculate the moles of carbon dioxide: n = PV / RT

Substituting the given values: n = (1 atm * 8.96 L) / (0.0821 atm L/mol K * 273 K)

Calculating the moles of carbon dioxide gives us: n = 0.363 mol

Calculating the moles of water (H2O):

To calculate the moles of water, we can use the molar mass of water, which is 18 g/mol.

Calculating the moles of water gives us: n = 10.8 g / 18 g/mol

n = 0.6 mol

Calculating the moles of carbon and hydrogen:

To find the empirical formula, we need to determine the ratio of carbon to hydrogen in the compound.

From the balanced equation for the combustion of hydrocarbons, we know that for every 1 mole of carbon dioxide produced, there are 1 mole of carbon atoms. Similarly, for every 1 mole of water produced, there are 2 moles of hydrogen atoms.

Using the moles of carbon dioxide and water calculated earlier, we can determine the moles of carbon and hydrogen: - Moles of carbon = 0.363 mol - Moles of hydrogen = 2 * 0.6 mol = 1.2 mol

Determining the empirical formula:

To find the empirical formula, we need to simplify the ratio of carbon to hydrogen to the simplest whole number ratio.

Dividing the moles of carbon and hydrogen by the smallest value (0.363 mol), we get: - Moles of carbon = 0.363 mol / 0.363 mol = 1 - Moles of hydrogen = 1.2 mol / 0.363 mol ≈ 3.31

Rounding the moles of hydrogen to the nearest whole number, we get: - Moles of hydrogen ≈ 3

Therefore, the empirical formula of the compound is CH3.

Determining the molecular formula:

To find the molecular formula, we need to know the molar mass of the compound. Unfortunately, the molar mass is not provided in the given information. Without the molar mass, we cannot determine the molecular formula.

Please provide the molar mass of the compound to determine the molecular formula.