Question

ХЕЛП СРОЧНО!! В химии вообще не бум бум а оценка за четверть решается 3. Составьте уравнения реакций согласно схеме: Ca-->CaO-->Ca(OH)2 4. Составьте уравнения реакций согласно схеме: Zn(OH)2-->ZnO-->...-->Zn(OH) (Должно получиться 3 уравнения) 5. Определите число формульных единиц и общее число атомов в навеске глауберовой соли Na2SO4 • 10H2O массой 6,44г

Answer 1

Ответ:

3) 2Ca+O2=2CaO  CaO+H2O=Ca(OH)2

Объяснение:

Answer 2

Chemical Reactions:

To solve the given problems, we need to write the balanced chemical equations for the reactions mentioned in the scheme.

1. Ca → CaO → Ca(OH)2: - The first reaction is the formation of calcium oxide (CaO) from calcium (Ca). - The second reaction is the formation of calcium hydroxide (Ca(OH)2) from calcium oxide (CaO).

The balanced chemical equations for these reactions are as follows: - Ca + O2 → CaO [[1]] - CaO + H2O → Ca(OH)2 [[2]]

2. Zn(OH)2 → ZnO → ... → Zn(OH): - The first reaction is the formation of zinc oxide (ZnO) from zinc hydroxide (Zn(OH)2). - The subsequent reactions involve the conversion of zinc oxide (ZnO) back to zinc hydroxide (Zn(OH)).

The balanced chemical equations for these reactions are as follows: - Zn(OH)2 → ZnO + H2O [[3]] - ZnO + H2O → Zn(OH) [[4]]

Please note that the scheme provided does not specify the intermediate reactions, so we cannot provide a complete set of three equations.

Calculation of Formula Units and Total Number of Atoms:

To determine the number of formula units and the total number of atoms in the given sample of sodium sulfate decahydrate (Na2SO4 • 10H2O) with a mass of 6.44 g, we need to use the molar mass and Avogadro's number.

1. Calculate the molar mass of Na2SO4 • 10H2O: - Na: 2 atoms x 22.99 g/mol = 45.98 g/mol - S: 1 atom x 32.07 g/mol = 32.07 g/mol - O: 4 atoms x 16.00 g/mol = 64.00 g/mol - H2O: 10 molecules x (2 atoms x 1.01 g/mol + 16.00 g/mol) = 360.40 g/mol

Total molar mass = 45.98 g/mol + 32.07 g/mol + 64.00 g/mol + 360.40 g/mol = 502.45 g/mol

2. Calculate the number of moles in the given sample: - Moles = Mass / Molar mass = 6.44 g / 502.45 g/mol = 0.0128 mol

3. Calculate the number of formula units: - Since there are 2 sodium ions (Na+) per formula unit, the number of formula units is: 0.0128 mol x (6.022 x 10^23 formula units/mol) x 2 = 1.54 x 10^22 formula units

4. Calculate the total number of atoms: - Each formula unit contains 2 sodium atoms (Na), 1 sulfur atom (S), 4 oxygen atoms (O), and 20 hydrogen atoms (H). - Total number of atoms = 1.54 x 10^22 formula units x (2 Na atoms + 1 S atom + 4 O atoms + 20 H atoms) = 1.54 x 10^22 x 27 = 4.16 x 10^23 atoms

Therefore, in the given sample of sodium sulfate decahydrate (Na2SO4 • 10H2O) with a mass of 6.44 g, there are approximately 1.54 x 10^22 formula units and a total of 4.16 x 10^23 atoms.