Question

Вычислите массовые доли элементов в процентах по формулам соединений: А) H3PO4; Б) Fe(NO3)2

Answer 1

Ответ:

w% (элемента) = Mr (элемента) : Mr (вещества) * 100%. Используя данную формулу, найдем массовые доли элементов в представленных соединениях: 1) СuSO4 : w% (Cu) = 64 : 160 * 100% = 40%.

Answer 2

Calculation of Mass Percent of Elements in Compounds

To calculate the mass percent of elements in compounds, we need to determine the molar mass of each element and the molar mass of the compound. Then, we can calculate the mass percent using the following formula:

Mass Percent = (Molar Mass of Element / Molar Mass of Compound) x 100%

Let's calculate the mass percent of elements in the given compounds:

A) H3PO4 (Phosphoric Acid)

To calculate the mass percent of elements in H3PO4, we need to determine the molar mass of each element and the molar mass of the compound.

The molar mass of hydrogen (H) is approximately 1.01 g/mol, the molar mass of phosphorus (P) is approximately 30.97 g/mol, and the molar mass of oxygen (O) is approximately 16.00 g/mol.

To calculate the molar mass of H3PO4, we multiply the molar mass of each element by the number of atoms present in the compound:

Molar Mass of H3PO4 = (3 x Molar Mass of H) + Molar Mass of P + (4 x Molar Mass of O)

Molar Mass of H3PO4 = (3 x 1.01 g/mol) + 30.97 g/mol + (4 x 16.00 g/mol)

Molar Mass of H3PO4 = 98.09 g/mol

Now, we can calculate the mass percent of each element in H3PO4:

- Mass Percent of Hydrogen (H) = (3 x Molar Mass of H) / Molar Mass of H3PO4 x 100% - Mass Percent of Phosphorus (P) = Molar Mass of P / Molar Mass of H3PO4 x 100% - Mass Percent of Oxygen (O) = (4 x Molar Mass of O) / Molar Mass of H3PO4 x 100%

Please note that the molar masses used in this calculation are approximate values and may vary slightly depending on the isotopic composition of the elements.

B) Fe(NO3)2 (Iron(II) Nitrate)

To calculate the mass percent of elements in Fe(NO3)2, we need to determine the molar mass of each element and the molar mass of the compound.

The molar mass of iron (Fe) is approximately 55.85 g/mol, the molar mass of nitrogen (N) is approximately 14.01 g/mol, and the molar mass of oxygen (O) is approximately 16.00 g/mol.

To calculate the molar mass of Fe(NO3)2, we multiply the molar mass of each element by the number of atoms present in the compound:

Molar Mass of Fe(NO3)2 = Molar Mass of Fe + (2 x Molar Mass of N) + (6 x Molar Mass of O)

Molar Mass of Fe(NO3)2 = 55.85 g/mol + (2 x 14.01 g/mol) + (6 x 16.00 g/mol)

Molar Mass of Fe(NO3)2 = 179.86 g/mol

Now, we can calculate the mass percent of each element in Fe(NO3)2:

- Mass Percent of Iron (Fe) = Molar Mass of Fe / Molar Mass of Fe(NO3)2 x 100% - Mass Percent of Nitrogen (N) = (2 x Molar Mass of N) / Molar Mass of Fe(NO3)2 x 100% - Mass Percent of Oxygen (O) = (6 x Molar Mass of O) / Molar Mass of Fe(NO3)2 x 100%

Please note that the molar masses used in this calculation are approximate values and may vary slightly depending on the isotopic composition of the elements.

Results:

A) H3PO4 (Phosphoric Acid): - Mass Percent of Hydrogen (H): 3.09% - Mass Percent of Phosphorus (P): 31.43% - Mass Percent of Oxygen (O): 65.48%

B) Fe(NO3)2 (Iron(II) Nitrate): - Mass Percent of Iron (Fe): 30.98% - Mass Percent of Nitrogen (N): 15.58% - Mass Percent of Oxygen (O): 53.44%

Please note that these calculations are based on the molar masses provided and may vary slightly depending on the actual isotopic composition of the elements.