Q11 of 38 Page 3

A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.

(i) Mass of boron in compound = 0.096 g

And, Mass of compound = 0.24 g


So, Percentage of boron =


                                  = 


                                  = 40% (1)


(ii) Mass of oxygen in compound = 0.144 g


And, Mass of compound = 0.24 g


So, Percentage of oxygen =


= 60% (2)


Thus, the percentage composition of the compound is: Boron = 40%; Oxygen = 60%

More from this chapter

All 38 →
9

In a reaction, 5.3 g of sodium carbonate reacted with 6 g ethanoic acid. The products were 2.2 g of carbon dioxide, o.9 g of water and 8.2 g of sodium ethanoate. Show that these observations are in agreement with the law of conservation of mass.

 10

Hydrogen and oxygen combine in the ratio of 1 : 8 by mass to from water. What mass of oxygen gas would be required to react completely with 3 g of hydrogen gas?

 12

The formula for the sulphate of a metal is MSO4. What is the formula for the chloride of that metal?

 13

If an element X has a valency of 3, then find out the formula of its chloride and sulphide.