Question

Вычислите массовую долю кислорода в молекулах H2О, H2SO4, Ca3(PO4)2 ??

Answer 1

H2O
w=M(O)*n:M(H2O)*100%=16*1:18*100%=88%
H2SO4
w=M(O)*n:M(H2SO4)*100%=16*4:98*100%=65.31%
Ca3(PO4)
w=M(O)*n:M(Ca3(PO4)2)*100%=16*8:310*100%=41.29%

Answer 2

Calculating the Mass Fraction of Oxygen in Molecules

To calculate the mass fraction of oxygen in the given molecules, we can use the molar masses of the elements and the molecular formulas. The molar mass of a substance is the mass of one mole of that substance and is expressed in grams per mole (g/mol).

1. Water (H2O): The molar mass of water (H2O) can be calculated as: - 2 atoms of hydrogen (H) with a molar mass of approximately 1.01 g/mol each - 1 atom of oxygen (O) with a molar mass of approximately 16.00 g/mol Therefore, the molar mass of water (H2O) is approximately 18.02 g/mol.

2. Sulfuric Acid (H2SO4): The molar mass of sulfuric acid (H2SO4) can be calculated as: - 2 atoms of hydrogen (H) with a molar mass of approximately 1.01 g/mol each - 1 atom of sulfur (S) with a molar mass of approximately 32.07 g/mol - 4 atoms of oxygen (O) with a molar mass of approximately 16.00 g/mol each Therefore, the molar mass of sulfuric acid (H2SO4) is approximately 98.08 g/mol.

3. Calcium Phosphate (Ca3(PO4)2): The molar mass of calcium phosphate (Ca3(PO4)2) can be calculated as: - 3 atoms of calcium (Ca) with a molar mass of approximately 40.08 g/mol each - 2 atoms of phosphorus (P) with a molar mass of approximately 30.97 g/mol each - 8 atoms of oxygen (O) with a molar mass of approximately 16.00 g/mol each Therefore, the molar mass of calcium phosphate (Ca3(PO4)2) is approximately 310.18 g/mol.

Calculating the Mass Fraction of Oxygen

Now, let's calculate the mass fraction of oxygen in each of the given molecules.

1. Water (H2O): The mass fraction of oxygen in water (H2O) can be calculated as: - The molar mass of oxygen in water is 16.00 g/mol. - The total molar mass of water is 18.02 g/mol. Therefore, the mass fraction of oxygen in water (H2O) is approximately 88.81%.

2. Sulfuric Acid (H2SO4): The mass fraction of oxygen in sulfuric acid (H2SO4) can be calculated as: - The molar mass of oxygen in sulfuric acid is 64.00 g/mol (4 atoms of oxygen). - The total molar mass of sulfuric acid is 98.08 g/mol. Therefore, the mass fraction of oxygen in sulfuric acid (H2SO4) is approximately 65.31%.

3. Calcium Phosphate (Ca3(PO4)2): The mass fraction of oxygen in calcium phosphate (Ca3(PO4)2) can be calculated as: - The molar mass of oxygen in calcium phosphate is 128.00 g/mol (8 atoms of oxygen). - The total molar mass of calcium phosphate is 310.18 g/mol. Therefore, the mass fraction of oxygen in calcium phosphate (Ca3(PO4)2) is approximately 41.25%.

In summary: - The mass fraction of oxygen in water (H2O) is approximately 88.81%. - The mass fraction of oxygen in sulfuric acid (H2SO4) is approximately 65.31%. - The mass fraction of oxygen in calcium phosphate (Ca3(PO4)2) is approximately 41.25%.