Answer: 20 mg Te-99 remains after 12 hours.
Explanation: N(t) = N(0)*(1/2)^(t/t1/2)
N(t) = (80 mg)*(0.5)^(12/6)
N(t) = 20 mg remains after 12 hours
Answer:
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<span>R-COOH
-COOH is the group, that shows that the substance is an organic acid.
Answer is B. Acids</span>
