Q3 of 27 Page 46

The atomic mass of helium is 4 and that of oxygen is 16. How many grams of helium is required to get as many number of atoms as are present in 40 g of oxygen.

(40 g, 160 g, 10 g, 4 g)

Given:

Atomic mass of helium = 4


Atomic mass of oxygen = 16


Mass of oxygen = 40 g


Hence, we can write



By putting the values, we get:



By applying criss cross method:



We get:


Mass of helium × 16 = 4 × 40g



Mass of helium = 10g


Thus, 10 grams of helium is required.


More from this chapter

All 27 →
1

Suppose 20 molecules of hydrogen are allowed to react with 20 molecules of oxygen to produce water.

a. Which of the reactant molecules gets consumed first?


b. The molecules of which reactant will remain unreacted? How many?

 2

Which, among the following, is used as the basis for expressing atomic mass?

(Hydrogen, Carbon - 12, Carbon - 14, Oxygen - 16)

 4

Find the number of gram atomic masses in each of the following.

100 g of helium


(Atomic mass He = 4, O = 16, N = 14, Ca = 40)

 4

Find the number of gram atomic masses in each of the following.

200 g of oxygen


(Atomic mass He = 4, O = 16, N = 14, Ca = 40)