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78.54 of nitrogen dioxide contain how many molecules

User RomanGor
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To calculate the number of molecules in a given amount of a substance, we need to know the molar mass of the substance and use Avogadro's number.

Given:

Amount of nitrogen dioxide (NO2) = 78.54 g

To determine the number of molecules, we'll follow these steps:

Calculate the number of moles of nitrogen dioxide:

Number of moles = Mass / Molar mass

The molar mass of nitrogen dioxide (NO2) can be calculated as follows:

Molar mass of NO2 = (Molar mass of N) + 2 × (Molar mass of O)

The molar masses are:

Molar mass of N = 14.01 g/mol

Molar mass of O = 16.00 g/mol

Molar mass of NO2 = 14.01 g/mol + 2 × 16.00 g/mol = 46.01 g/mol

Plugging in the values, we have:

Number of moles = 78.54 g / 46.01 g/mol

Calculate the number of molecules:

Number of molecules = Number of moles × Avogadro's number

Avogadro's number = 6.022 × 10^23 molecules/mol

Plugging in the values, we have:

Number of molecules = Number of moles × Avogadro's number

Now, let's calculate:

Number of moles = 78.54 g / 46.01 g/mol ≈ 1.7078 mol

Number of molecules = 1.7078 mol × 6.022 × 10^23 molecules/mol

Number of molecules ≈ 1.028 × 10^24 molecules

Therefore, approximately 1.028 × 10^24 molecules are present in 78.54 grams of nitrogen dioxide (NO2).

User Jochem Toolenaar
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