Question

Помогите пожалуйста! Срочно нужно! Какова молекулярная формула вещества в котором массовая доля углерода равна 0.52 кислорода 0,35 водорода 0,13?.Относительная плотность вещества по водороду равна 23

Answer 1

CxHyOz
x:y:z =  $\frac{52}{12}: \frac{13}{1}: \frac{35}{16}$= 4,33: 13: 2.19
Делим все на наименьшее- на 2,19,получаем:
2: 6:1
С2H6O
Проверяем:
M(CxHyOz)= D по H2* M(H2)= 23*2=46 г/моль
M(C2H6O)= 12*2+6*1+16= 46 г/моль

Answer 2

Molecular Formula Calculation

To determine the molecular formula of a substance based on its mass fractions, we need to convert the mass fractions into mole fractions. The mole fraction of an element is the ratio of the number of moles of that element to the total number of moles in the substance.

Given the mass fractions of carbon (0.52), oxygen (0.35), and hydrogen (0.13), we can calculate the mole fractions as follows:

1. Calculate the number of moles of each element: - Moles of carbon = mass fraction of carbon * relative molecular mass of carbon - Moles of oxygen = mass fraction of oxygen * relative molecular mass of oxygen - Moles of hydrogen = mass fraction of hydrogen * relative molecular mass of hydrogen

2. Calculate the total number of moles in the substance: - Total moles = moles of carbon + moles of oxygen + moles of hydrogen

3. Calculate the mole fractions of each element: - Mole fraction of carbon = moles of carbon / total moles - Mole fraction of oxygen = moles of oxygen / total moles - Mole fraction of hydrogen = moles of hydrogen / total moles

Now, let's calculate the molecular formula using the given mass fractions and relative density.

Calculation Steps

1. Calculate the number of moles of each element: - Moles of carbon = 0.52 * relative molecular mass of carbon - Moles of oxygen = 0.35 * relative molecular mass of oxygen - Moles of hydrogen = 0.13 * relative molecular mass of hydrogen

2. Calculate the total number of moles in the substance: - Total moles = moles of carbon + moles of oxygen + moles of hydrogen

3. Calculate the mole fractions of each element: - Mole fraction of carbon = moles of carbon / total moles - Mole fraction of oxygen = moles of oxygen / total moles - Mole fraction of hydrogen = moles of hydrogen / total moles

4. Determine the empirical formula: - The empirical formula represents the simplest whole number ratio of atoms in a compound. To find the empirical formula, divide the mole fractions by the smallest mole fraction to obtain the simplest ratio.

5. Determine the molecular formula: - The molecular formula represents the actual number of atoms of each element in a molecule. To find the molecular formula, multiply the empirical formula by an integer factor that gives the desired relative density.

Now, let's calculate the molecular formula using the given mass fractions and relative density.

Calculation Example

Given: - Mass fraction of carbon = 0.52 - Mass fraction of oxygen = 0.35 - Mass fraction of hydrogen = 0.13 - Relative density (relative to hydrogen) = 23

1. Calculate the number of moles of each element: - Moles of carbon = 0.52 * 12 (relative molecular mass of carbon) = 6.24 - Moles of oxygen = 0.35 * 16 (relative molecular mass of oxygen) = 5.6 - Moles of hydrogen = 0.13 * 1 (relative molecular mass of hydrogen) = 0.13

2. Calculate the total number of moles in the substance: - Total moles = 6.24 + 5.6 + 0.13 = 11.97

3. Calculate the mole fractions of each element: - Mole fraction of carbon = 6.24 / 11.97 = 0.52 - Mole fraction of oxygen = 5.6 / 11.97 = 0.47 - Mole fraction of hydrogen = 0.13 / 11.97 = 0.01

4. Determine the empirical formula: - The smallest mole fraction is 0.01, corresponding to hydrogen. Dividing the mole fractions by 0.01 gives the simplest ratio: carbon: 52, oxygen: 47, hydrogen: 1.

5. Determine the molecular formula: - To find the molecular formula, we need to multiply the empirical formula by an integer factor that gives the desired relative density. In this case, the relative density is 23 (relative to hydrogen). - The empirical formula is CH2O (carbon: 52, hydrogen: 1, oxygen: 47). - To obtain a relative density of 23, we need to multiply the empirical formula by a factor of 23. - The molecular formula is therefore C23H46O23.

The molecular formula of the substance, given the mass fractions and relative density, is C23H46O23.