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**ONE CHEMISTRY QUESTION**

**ONE CHEMISTRY QUESTION**-example-1
**ONE CHEMISTRY QUESTION**-example-1
**ONE CHEMISTRY QUESTION**-example-2
User Kyaw
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Answer:

A) 0.30 moles.

B) it contains 0.3 moles of both Na and Cl.

C) it contains 6.023 x 10²³ atoms of both Na and Cl.

Step-by-step explanation:

A) The number of moles of 17.45 g of NaCl:

n = mass / molar mass,

mass = 17.45 g and molar mass = 58.44 g/mol

The number of moles of NaCl = (17.45 g) / (58.44 g/mol) = 0.298 mol ≅ 0.30 moles.

B) The number of moles of each element in NaCl

NaCl → Na + Cl

Each mole of NaCl contains one mole of Na and one mole of Cl.

using cross multiplication:

1.0 mol NaCl → 1.0 mol Na

0.3 mol NaCl → ??? mol Na

The number of moles of Na atoms in NaCl = (1.0 mol Na x 0.3 mol NaCl) / (1.0 mol NaCl) = 0.3 mol of Na atoms.

by the same way; the number of moles of Cl atoms = (1.0 mol Cl x 0.3 mol NaCl) / (1.0 mol NaCl) = 0.3 mol of Cl atoms.

C) The number of atoms of each element in the sample:

It is known that every mole of a substance contains Avogadro,s number (NA = 6.023 x 10²³) of molecules.

1.0 mole of NaCl → 6.023 x 10²³ molecules

0.3 mole of NaCl → ???? molecules

using cross multiplication:

The number of molecules in 0.3 mole of NaCl = (6.023 x 10²³ x 0.3 mole) / (1.0 mole) = 1.8069 x 10²³ molecules.

Every molecule of NaCl contains one atom of Na and one atom of Cl.

So, it contains 6.023 x 10²³ atoms of both Na and Cl.

User Arman Iqbal
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