Radioactive Tracers Are Useful in Studying Very Low Concentrations of Chemical

question 56

Multiple Choice

Radioactive tracers are useful in studying very low concentrations of chemical species. A chemist has a sample of HgI₂ in which part of the iodine is the radioactive nuclide of mass 131, so that the count rate is 5.0  10¹¹ counts per minute per mole of I. The solid mercuric iodide is placed in water and allowed to come to equilibrium. Then 100 mL of the solution is withdrawn, and its radioactivity is measured and found to give 22 counts per minute. What is the molar concentration of iodide ion in the solution?

• A) 1.1  10^-11
• B) 1.1  10^-9
• C) 1.1  10^-10
• D) 4.4  10^-10
• E) 4.4  10^-11

Recognize the importance of environmental factors and community infrastructure in disease prevention.

Understand the historical development of public health initiatives and their impact on community health.

Analyze the role of government and non-governmental organizations in the advancement of public health.

Identify key figures and their contributions to public health and nursing.

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Definitions:

Lymph Tissue

A vital part of the immune system, made up of organs and cells that produce, store, and carry cells that fight infection.

Preoperational

Referring to Piaget's stage of cognitive development in children aged 2-7, characterized by symbolic thinking and difficulty understanding others' perspectives.

Secondary Circular Reaction

A stage in Piaget's theory of cognitive development where infants (4-8 months) repeat actions to get desired outcomes, showing the beginning of intentional behavior.

Tertiary Circular Reaction

A concept in cognitive development referring to a stage in Piaget's model where infants 12-18 months old purposefully experiment with different actions to observe outcomes.