A compound of nitrogen and oxygen was found to contain 7: 16 by mass N and O respectively. Calculate molecular formula if vapour density is 46.

 Answer Key: ( N2O4)

A mixture of blue and green balls contains 25% by number blue balls. Mass of each blue balls is 40 gm and mass of each green balls is 20 gm calculate (1) Average mass of ball (2) % by mass

Answer Key: (1) 25 gm (2) 40 %