like How many moles are there in 9.07 x 1023 molecules of propane?

How many SiH4 molecules are there in 9.83 moles of SiH4?

How many molecules are there in 17.8 g of PF3?

How many carbon dioxide molecules are there in 5.79 moles of carbon dioxide?You will need to divide your answer by 1.0x1023

1 mole = 6.022*10^23 molecules
mole of propane=    9.07 x 1023 molecules of propane * 1mole / 6.022*10^23 molecules
SiH4 molecules = 9.83 moles of SiH4*6.022*10^23 molecules

molecules are there in 17.8 g of PF3
convert 17.8 g of PF3 into moles of PF3 by using 17.8 g X 1mole/ molar mass of PF3
then convert moles into number of molecules by using ratio 6.022*10^23 molecules / 1mole
Carbon dioxide molecules= 5.79 moles of carbon dioxide X 6.022*10^23 molecules / 1mole