Question

Calculate the mass defect of the helium nucleus 32he. the mass of neutral 32he is given by mhe=3.016029amu. express your answer in atomic mass units to four significant figures.

Answer 1

Answer: 0.007044 g

Explanation:

1) mass defect is the difference between the mass of the nucleus and the sum of the masses of the protons and neutrons.

3) He has two protons.

4) The istope given is ³₂ He, which means it has 2 protons and 1 neutron.

5) The masses of neutrons and protons are taken from a table (from a textbook or the internet)

Mass of 2 mol of protons: 2 × 6.022 × 10 ²³ protons/mol × 1.6726 × 10 ⁻²⁴ g/mol = 2.014447944 g

Mass of 1 mol of neutrons = 1 × 6.022 × 10²³ neutrons/mol × 1.6749 × 10 ⁻²⁴ g/mol = 1.00862478 g

Sum = 2.014447944 g + 1.00862478 g = 3.023072724 g

6) mass deffect = 3.023072724g - 3.016029 g = 0.007043724

7) Round to 4 significant figures: 0.007044 g

That is the answer: 0.007044 g