Question

определить сколько молекул и всех атомов содержится в 91г сульфида натрия

Answer 1

 n= m|M      M(Na2So4)=23*2++32+16*4=142г\моль
  n= 91г \ 142 г\моль=0.6 моль
N= n* N Авогадро= 0.6 моль*6  *10 в 23 степени молекул/моль= 36*10 в 22 степени молекул/моль

Answer 2

Calculation of the Number of Molecules and Atoms in 91g of Sodium Sulfide

To determine the number of molecules and atoms in 91 grams of sodium sulfide (Na2S), we need to use the molar mass and Avogadro's number.

1. Calculate the molar mass of sodium sulfide (Na2S): - The molar mass of sodium (Na) is approximately 22.99 grams per mole (g/mol). - The molar mass of sulfur (S) is approximately 32.07 g/mol. - Since there are two sodium atoms and one sulfur atom in each molecule of sodium sulfide, we can calculate the molar mass as follows: Molar mass of Na2S = (2 * molar mass of Na) + molar mass of S = (2 * 22.99 g/mol) + 32.07 g/mol = 45.98 g/mol + 32.07 g/mol = 78.05 g/mol

2. Calculate the number of moles of sodium sulfide: - We can use the formula: moles = mass / molar mass - Given that the mass of sodium sulfide is 91 grams, we can calculate the number of moles as follows: Moles of Na2S = 91 g / 78.05 g/mol ≈ 1.166 moles

3. Calculate the number of molecules: - Avogadro's number states that there are approximately 6.022 x 10^23 entities (atoms, molecules, ions, etc.) in one mole of a substance. - Therefore, the number of molecules in 1.166 moles of sodium sulfide is: Number of molecules = 1.166 moles * (6.022 x 10^23 molecules/mol) ≈ 7.01 x 10^23 molecules

4. Calculate the number of atoms: - Since there are two sodium atoms and one sulfur atom in each molecule of sodium sulfide, we can calculate the number of atoms as follows: Number of atoms = Number of molecules * (2 sodium atoms + 1 sulfur atom) = 7.01 x 10^23 molecules * (2 + 1) = 7.01 x 10^23 molecules * 3 ≈ 2.10 x 10^24 atoms

Therefore, in 91 grams of sodium sulfide, there are approximately 7.01 x 10^23 molecules and 2.10 x 10^24 atoms.