Question

The atomic mass of \[\ce{^32_16S}\] is 31.97 u. If masses of neutron and H atom are 1.0087 u and 1.0078 u respectively. What is the mass defect?

Answer 1

Given: m = 31.97 u, Z = 16, A = 32, m_n = 1.0087 u, m_H = 1.0078 u

To find: ∆m

Formula: ∆m = Zm_H + (A - Z)m_n - m

Calculation: ∆m = Zm_H + (A - Z)m_n - m

= 16 × 1.0078 + (16 × 1.0087) – 31.97

= [16.1248 + 16.1392] - 31.97

= 0.294 u

The mass defect is 0.294 u.