Question

1.Визначити валентність елементів в наступних формулах оксидів: BaO,CuO,P2O5,Cl2O7,CO2,NO,CO,SiO,NO,N2O,NiO,Fe2O3. 2.Обчисліть масову частку Оксигену в молекулі H2CO3

Answer 1

Ответ:

Объяснение:

1) Ba(II)O(II),  Cu(II)O(II),  P(V)O(II),   Cl(VII)O(II),  C(IV)O(II),  N(II)O(II),  C(II)O(II),  Si(II)O(II),  N(II)O(II),  N(I)O(II),  Ni(II)O(II),  F(III)O(II)

2) Mr(H2CO3) = 1*2 + 12 + 16*3 =62

W(O) = Ar(O) *n / Mr(H2CO3)  *100% = 16*3 / 62  *100% =77%

Answer 2

Valence of Elements in Oxides:

To determine the valence of elements in the given formulas of oxides, we need to consider the oxidation states of the elements. The oxidation state of an element in a compound indicates the number of electrons gained or lost by that element.

1. BaO (Barium Oxide): - Barium (Ba) is an alkaline earth metal and typically has a valence of +2. - Oxygen (O) usually has a valence of -2. - Therefore, the valence of Ba in BaO is +2, and the valence of O is -2.

2. CuO (Copper(II) Oxide): - Copper (Cu) can have multiple oxidation states, but in this case, it is in the +2 oxidation state. - Oxygen (O) has a valence of -2. - Therefore, the valence of Cu in CuO is +2, and the valence of O is -2.

3. P2O5 (Phosphorus Pentoxide): - Phosphorus (P) can have multiple oxidation states, but in this case, it is in the +5 oxidation state. - Oxygen (O) has a valence of -2. - Therefore, the valence of P in P2O5 is +5, and the valence of O is -2.

4. Cl2O7 (Dichlorine Heptoxide): - Chlorine (Cl) typically has a valence of -1. - Oxygen (O) has a valence of -2. - Therefore, the valence of Cl in Cl2O7 is -1, and the valence of O is -2.

5. CO2 (Carbon Dioxide): - Carbon (C) typically has a valence of +4. - Oxygen (O) has a valence of -2. - Therefore, the valence of C in CO2 is +4, and the valence of O is -2.

6. NO (Nitric Oxide): - Nitrogen (N) typically has a valence of +2. - Oxygen (O) has a valence of -2. - Therefore, the valence of N in NO is +2, and the valence of O is -2.

7. CO (Carbon Monoxide): - Carbon (C) typically has a valence of +2. - Oxygen (O) has a valence of -2. - Therefore, the valence of C in CO is +2, and the valence of O is -2.

8. SiO (Silicon Monoxide): - Silicon (Si) typically has a valence of +4. - Oxygen (O) has a valence of -2. - Therefore, the valence of Si in SiO is +4, and the valence of O is -2.

9. NO (Nitric Oxide): - Nitrogen (N) typically has a valence of +2. - Oxygen (O) has a valence of -2. - Therefore, the valence of N in NO is +2, and the valence of O is -2.

10. N2O (Nitrous Oxide): - Nitrogen (N) typically has a valence of +1 or +3. - Oxygen (O) has a valence of -2. - In N2O, the valence of N is +1 and the valence of O is -2.

11. NiO (Nickel(II) Oxide): - Nickel (Ni) can have multiple oxidation states, but in this case, it is in the +2 oxidation state. - Oxygen (O) has a valence of -2. - Therefore, the valence of Ni in NiO is +2, and the valence of O is -2.

12. Fe2O3 (Iron(III) Oxide): - Iron (Fe) can have multiple oxidation states, but in this case, it is in the +3 oxidation state. - Oxygen (O) has a valence of -2. - Therefore, the valence of Fe in Fe2O3 is +3, and the valence of O is -2.

Mass Fraction of Oxygen in H2CO3:

To calculate the mass fraction of oxygen in the molecule H2CO3 (carbonic acid), we need to determine the molar mass of oxygen and the molar mass of the entire molecule.

The molar mass of oxygen (O) is approximately 16.00 g/mol.

The molar mass of H2CO3 can be calculated as follows: - Hydrogen (H) has a molar mass of approximately 1.01 g/mol. - Carbon (C) has a molar mass of approximately 12.01 g/mol. - Oxygen (O) has a molar mass of approximately 16.00 g/mol.

Therefore, the molar mass of H2CO3 is: (2 * 1.01 g/mol) + 12.01 g/mol + (3 * 16.00 g/mol) = 62.03 g/mol.

To calculate the mass fraction of oxygen in H2CO3, we divide the molar mass of oxygen by the molar mass of H2CO3 and multiply by 100%: (3 * 16.00 g/mol) / 62.03 g/mol ≈ 0.774.

The mass fraction of oxygen in H2CO3 is approximately 77.4%.