When 3.0 g

Answer will be governed by the law of constant proportions which states that the mass of reactant must be equal to the mass of the product formed during a reaction

Now, since carbon and oxygen combine in the fixed proportion of 3 : 8 by mass to produce 11 g of carbon dioxide,

  
   3    +   8    =   11 (by ratio proportion)

According to the question, the equation formed will be:-


3    +  50      =   11         +   42   
    53            =            53

Therefore, the same mass of carbon dioxide (11 g) will be obtained even if we burn 3 g of carbon in 50 g of oxygen.
The extra oxygen (50 – 8 = 42 g oxygen) will remain unchanged.