Question

при сгорании вещества массой 4,22 образуется 13,2 г оксида углерода (4) и 5,4 г H2O.плотность паров этоговещества по воздуху равна 2,9.Определите молекулярную формулу данного вещества.

Answer 1

С--->CO2, 2H--->H2O
x=(9, 9*12)/44=2,7 y=(4,5*2)/18=0,5
x:y=(2,7/12):0,5/1=0,225:0,5=> 0,225/0,225:0,5/0,225=1:2
M(CH2)=12+2=14
М истинная=D вещества/возд.*29=2*29=58
Формула углеводорода - С4Н10
М (С4Н10)=12*4+10=58

Answer 2

Calculation of Molar Mass

To determine the molecular formula of the substance, we need to calculate the molar mass of the given products.

The given information states that when a substance with a mass of 4.22 g burns, it produces 13.2 g of carbon monoxide (CO) and 5.4 g of water (H2O).

To calculate the molar mass, we need to convert the masses of the products into moles. We can use the molar masses of carbon (C), oxygen (O), and hydrogen (H) to perform the calculations.

The molar mass of carbon (C) is approximately 12.01 g/mol, the molar mass of oxygen (O) is approximately 16.00 g/mol, and the molar mass of hydrogen (H) is approximately 1.01 g/mol.

Using these molar masses, we can calculate the number of moles of carbon monoxide (CO) and water (H2O) produced:

- Moles of CO = mass of CO / molar mass of CO - Moles of H2O = mass of H2O / molar mass of H2O

Let's perform the calculations:

Moles of CO = 13.2 g / (12.01 g/mol + 16.00 g/mol) = 0.55 mol Moles of H2O = 5.4 g / (2 * 1.01 g/mol + 16.00 g/mol) = 0.30 mol

Determining the Empirical Formula

To determine the empirical formula, we need to find the simplest whole-number ratio of the atoms in the compound. We can do this by dividing the number of moles of each element by the smallest number of moles.

In this case, the smallest number of moles is 0.30 mol (moles of H2O). Dividing the moles of CO and H2O by 0.30 mol, we get:

Moles of CO / 0.30 mol = 0.55 mol / 0.30 mol ≈ 1.83 Moles of H2O / 0.30 mol = 0.30 mol / 0.30 mol = 1.00

Rounding these ratios to the nearest whole number, we get approximately:

CO: 2 H2O: 1

Therefore, the empirical formula of the substance is CO2H2O.

Determining the Molecular Formula

To determine the molecular formula, we need to find the actual number of atoms of each element in the compound. We can do this by multiplying the subscripts in the empirical formula by an integer (n) that gives the molar mass of the compound.

To find the value of n, we need to calculate the molar mass of the empirical formula (CO2H2O) and compare it to the given molar mass of the substance.

The molar mass of CO2H2O can be calculated as follows:

Molar mass of CO2H2O = (molar mass of C * 1) + (molar mass of O * 2) + (molar mass of H * 2) + (molar mass of O * 1)

Substituting the molar masses of C, O, and H, we get:

Molar mass of CO2H2O = (12.01 g/mol * 1) + (16.00 g/mol * 2) + (1.01 g/mol * 2) + (16.00 g/mol * 1) = 44.03 g/mol

Now, we can calculate the value of n by dividing the given molar mass of the substance by the molar mass of the empirical formula:

n = molar mass of the substance / molar mass of CO2H2O

Given that the molar mass of the substance is 4.22 g, we can calculate n as follows:

n = 4.22 g / 44.03 g/mol ≈ 0.096

Rounding this value to the nearest whole number, we get approximately:

n ≈ 0

Therefore, the molecular formula of the substance is CO2H2O.

Note: The given information does not provide enough data to determine the exact molecular formula of the substance. The molecular formula CO2H2O represents the simplest whole-number ratio of the atoms in the compound, but without additional information, we cannot determine the exact number of atoms in the molecule.