A First-Order Reaction Has a Half-Life of 20

question 34

Multiple Choice

A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 *10²⁰ molecules of reactant at time t = 0, how many molecules remain unreacted after 100.0 minutes?

• A) 1.00 * 10⁴ molecules
• B) 2.00 * 10¹⁹ molecules
• C) 3.20 *10¹⁶ molecules
• D) 5.00 * 10²⁰ molecules
• E) None of these choices is correct.

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