Chemistry

Problem

1.0\,\text{g}

sample of a radioactive isotope has a half-life of

20\,\text{min}

. After

20\,\text{min}

, exactly

0.25\,\text{g}

of the remaining sample is physically removed. What mass of the isotope will still be present after a further

20\,\text{min}

? a)

0.375\,\text{g}

0.125\,\text{g}

0.25\,\text{g}

0.50\,\text{g}