Question

Find out the GMM of the following. Also find out the total number of atoms. 

a. 20 g Nitrogen (H₂) 

b. 88.75 g Chlorine (Cl₂) 

c. 4 g Calcium (Ca₂) , 

d. 7.75 g phosphorus (p₄) 

(H = 1, Cl =35.5, Ca =40, P=31)

Answer 1

a. 20 g of hydrogen (H₂): GMM = \(\frac{20}{2}\) = 10 Number of molecules = 10 × 6.022 × 10²³

Total number of atoms = 2 × 10 × 6.022 × 10²³ 

= 20 × 6.022 × 10²³

b. 88.75 g of chlorine 

Number of GMM = \(\frac{88.75}{71}\) = 1.25

Number of molecules = 1.25 × 6.022 × 10²³

Total number of atoms = 2 × 1.25 × 6.022 × 10²³ 

= 2.5 × 6.022 × 10²³

c. 4 g Calcium (Ca) 

Number of GMM = \(\frac{4}{40}\) = \(\frac{1}{10}\) = 0.1 

Number of molecules = 0.1 × 6.022 × 10²³

Total number of atoms = 1 × 0.1 × 6.022 × 10²³ 

= 0.1 × 6.022 × 10²³ 

d. 7.75 g Phosphorus Number of GMM = \(\frac{7.75}{31}\) = \(\frac{1}{4}\) = 0.25 

Number of molecules = 0.25 × 6.022 × 10²³