Chapter 18, Problem 44QAP

Interpretation Introduction

(a)

Interpretation:

The balanced chemical equation for the decay of Sr-90 needs to be determined.

Concept introduction:

A nuclear chemical equation is said to be balanced if there are same number of protons and neutrons are present on both side of the reaction arrow. The nuclear reactions take place by emission of alpha, beta and gamma particles from the different isotopes of the atoms.

Interpretation Introduction

(b)

Interpretation:

The value of $\Delta m$ for decay of 1 mol of Sr-90 needs to be determined.

Concept introduction:

The mass defect for any nuclear reaction is the change in masses of the species involved in the process.

For a general nuclear reaction as follows:

$A\to B+C$

The mass defect can be calculated as follows:

$m_B+m_C-m_A$

Here, m is atomic mass of A, B and C atoms.

Interpretation Introduction

(c)

Interpretation:

The amount of energy released by the decay of 6.50 mg of Sr-90 needs to be determined.

Concept introduction:

From the mass defect, the change in energy can be calculated as follows:

$\Delta E=\Delta m{c}^2$

Here, $\Delta m$ is change in mass and c is speed of light. If the value is negative, the energy is released, if it is positive the energy is required for the reaction.