How many moles of oxygen are in 49.2 grams of carbon dioxide?

Number of mole in Oxygen = 2.24 mol

Explanation:

Given:

Amount of carbon dioxide (CO₂) = 49.2 gram

Find:

Number of moles in Oxygen

Computation:

Molecular weight of CO₂ = 44 gram (Approx)

Number of mole in CO₂ = 49.2 / 44

Number of mole in CO₂ = 1.11818182 mol

CO₂ has 2 mole of Oxygen,

So,

Number of mole in Oxygen = 2 × 1.11818182

Number of mole in Oxygen = 2.23636364

Number of mole in Oxygen = 2.24 mol

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"