To find the mass of 1.40 x 10^25 molecules of NO2, we need to follow these steps:
1. Determine the molar mass of NO2:
- Nitrogen (N) has a molar mass of approximately 14.01 g/mol.
- Oxygen (O) has a molar mass of approximately 16.00 g/mol.
- The molar mass of NO2 is the sum of the molar masses of nitrogen and two oxygen atoms: 14.01 + 2(16.00) = 46.01 g/mol.
2. Calculate the number of moles in 1.40 x 10^25 molecules of NO2:
- Avogadro's number tells us that 1 mole of any substance contains 6.022 x 10^23 molecules.
- To find the number of moles in 1.40 x 10^25 molecules of NO2, we divide the given number of molecules by Avogadro's number:
\( \frac{1.40 \times 10^{25} \text{ molecules}}{6.022 \times 10^{23} \text{ molecules/mol}} \)
3. Once we have the number of moles, we can calculate the mass:
- Mass = Number of moles x Molar mass
- Mass = (Number of moles from step 2) x (Molar mass from step 1)
By following these steps, you can determine the mass of 1.40 x 10^25 molecules of NO2.
