Question

Answer the two questions for 15pts

Answer 1

Answer:

For 1: 6.68 g of nitrogen dioxide will contain $8.73\times 10^{22}$ number of molecules

For 2: The given amount of nitrogen dioxide molecules has a mass of 41.31 g.

Explanation:

According to the mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of molecules

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

• For 1:

We are given:

Mass of nitrogen dioxide = 6.68 g

Molar mass of nitrogen dioxide = 46 g/mol

Putting values in equation 1, we get:

$\text{Moles of nitrogen dioxide}=\frac{6.68g}{46g/mol}=0.145mol$

Using above concept:

If 1 mole of a compound contains $6.022\times 10^{23}$ number of molecules

So, 0.145 moles of nitrogen dioxide will contain = $(0.145\times 6.022\times 10^{23})=8.73\times 10^{22}$ number of molecules

Hence, 6.68 g of nitrogen dioxide will contain $8.73\times 10^{22}$ number of molecules

• For 2:

We are given:

Molecules of nitrogen dioxide = $5.41\times 10^{22}$ molecules

Using the above concept:

If $6.022\times 10^{23}$ number of molecules are present in 1 mole of a compound

So, $5.41\times 10^{22}$ number of molecules will be present in = $\frac{1mol}{6.022\times 10^{23}}\times 5.41\times 10^{22}=0.898$ moles of nitrogen dioxide

We know, molar mass of nitrogen dioxide = 46 g/mol

Using equation 1:

$0.898mol=\frac{\text{Mass of nitrogen dioxide}}{46g/mol}\\\\\text{Mass of nitrogen dioxide}=0.898mol\times 46g/mol=41.31g$

Hence, the given amount of nitrogen dioxide molecules has a mass of 41.31 g.