How many molecules of carbon dioxide are in 243.6 g of carbon dioxide?

Hey there ! 

Molar mass carbon dioxide:

CO2 = 44.01 g/mol

1) number of moles :

1 mole CO2 44.01 g
(moles CO2) 243.6 g

moles CO2 = 243.6 * 1 / 44.01

moles CO2 = 243.6 / 44.01

=> 5.535 moles of CO2

Therefore:

1 mole 6.02x10²³ molecules
5.535 moles ( molecules CO2)

molecules CO2 = 5.535 * ( 6.02x10²³) / 1

=> 3.33x10²⁴ molecules of CO2

The pOH is 2.603

Explanation:

The formula for finding pOH by pH is simply subtracting the pH from 14

pOH=14-11.397

pOH=2.603