How many molecules of CO2 are contained in 4.40g of CO2

6.02 x 10²²molecules

Explanation:

Given parameters:

Mass of CO₂  = 4.4g

Unknown:

Number of molecules in CO₂  = ?

Solution:

To find the number of molecules in the given mass, we have to find the number of moles in the compound first;

   Number of moles  =  

Molar mass of CO₂  = 12 + 2(16) = 44g/mol

Insert the parameters and solve;

   Number of moles  =   =  0.1mol

  1 mole of a substance contains 6.02 x 10²³molecules

  0.1 mole of CO₂ will contain 0.1 x 6.02 x 10²³molecules

                                                 = 6.02 x 10²²molecules

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.