Sodium-24 Has a Half-Life of 15

question 52

Multiple Choice

Sodium-24 has a half-life of 15.0 hours. Suppose you had a sample containing 0.010 moles of Na-24. How many hours would be required to reduce your sample to 6.25 × 10 ^{− 4} moles?

• A)120
• B)60
• C)45
• D)30

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Definitions:

Conditioned Response

A learned reaction to a previously neutral stimulus that occurs as a result of conditioning, typically demonstrated in Pavlov’s dog experiment.

Unconditioned Response

A spontaneous, innate response to a trigger that happens without any previous training or conditioning.

Conditioned Stimulus

A previously neutral stimulus that, after association with an unconditioned stimulus, comes to trigger a conditioned response.

Unconditioned Stimulus

A stimulus that naturally and automatically triggers an unconditioned response without prior conditioning.