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Ch.21 - Nuclear Chemistry
Chapter 21, Problem 69a

A laboratory rat is exposed to an alpha-radiation source whose activity is 14.3 mCi. (a) What is the activity of the radiation in disintegrations per second? In becquerels?

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1. The activity of a radioactive source is given in curies (Ci), where 1 Ci is equivalent to 3.7 x 10^10 disintegrations per second (dps). The problem provides the activity in milliCuries (mCi), so first convert this to Curies by using the conversion factor 1 Ci = 1000 mCi.
2. Once you have the activity in Curies, convert this to disintegrations per second by using the conversion factor 1 Ci = 3.7 x 10^10 dps.
3. The activity of a radioactive source can also be given in becquerels (Bq), where 1 Bq is equivalent to 1 disintegration per second. Therefore, to convert the activity from disintegrations per second to becquerels, use the conversion factor 1 dps = 1 Bq.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Radioactivity and Disintegration

Radioactivity is the process by which unstable atomic nuclei lose energy by emitting radiation. This decay occurs in discrete events called disintegrations, which can be quantified. The activity of a radioactive source is a measure of the number of disintegrations occurring per unit time, typically expressed in counts per second.
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Curie and Becquerel

The Curie (Ci) and Becquerel (Bq) are units of radioactivity. One Curie is defined as 3.7 x 10^10 disintegrations per second, while one Becquerel is equivalent to one disintegration per second. To convert between these units, one must use the conversion factor, allowing for a clear understanding of the activity level of radioactive materials.
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Unit Conversion

Unit conversion is a mathematical process used to change a quantity expressed in one set of units to another. In the context of radioactivity, converting from millicuries (mCi) to disintegrations per second or becquerels requires applying appropriate conversion factors. Mastery of unit conversion is essential for accurately interpreting and communicating scientific measurements.
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Conversion Factors