Question

20) If you have 4.450 x 1025 individual formaldehyde (CH2O = 30.03 g/mol) molecules, and their density is 0.8150 g/mL., then how many mL of space do they occupy? ________ mL

Answer 1

Answer

2722.81 mL

Explanation

Given:

Density = 0.8150 g/mL

Molecular mass CH2O = 30.03 g/mol

Number of formaldehyde, CH2O molecules = 4.450 x 10²⁵ moelcules

You need to first convert the number of molecules of formaldehyde to moles.

To do this, divide the the number of molecules by Avogardro's number

$4.450\times10^{25}\text{ molecules }=\frac{4.450\times10^{25}}{6.022\times10^{23}}moles=73.89571571\text{ moles}$

Since molecular mass of 1 mole of CH2O = 30.03 g

Then, the mass of 73.89571571 moles will be

$30.03\times73.89571571=2219.088343\text{ g}$

Now we can calculate the mL of space (volume) occupied by the molecules using the formula below

$\text{Volume }=\frac{Mass}{Density}$$\text{Volume }=\frac{2219.088343\text{ g}}{0.8150\text{ g/mL}}=2722.81\text{ mL}$

2722.81 mL mL of space were occuppied by the formaldehyde.