1.0g of magnesium is burnt with 0.56 g `O_(2)` is a closed vessel. Which reactant is left in excess and how much (at wt. Mg=24, O=16)-

Options

A. `Mg,0.16g`
B. `O_(2),0.16g`
C. `Mg,0.44g`
D. `O_(2),0.28g`

Answer

A

Explanation

`n_(Mg)=(1)/(24)=0.0416 mol, n_(O_(2))=(0.56)/(32)=0.0175` mol
The balanced equation is
`{:(,Mg,+,(1)/(2)O_(2),to,MgO),("Initial:",0.0416" mol",,0.0175mol,,0),("Final:",(0.0416-2xx0.0175),,0,,2xx0.0175),(,=0.0066" mol",,(O_(2)" is limiting agent"),,):}`
`therefore`Mass of Mg left in excess`=0.0066xx24=0.16g`.