Answer
16.84%
Work Step by Step
The percentage of oxygen in the substance is determined by the following equation:
$\%O = \frac{(number -of -oxygen- atoms)\times(atomic- mass- of- oxygen)}{molecular- mass -of- morphine}\times100\%$
So, molecular mass of morphine is:
MM(Morphine)= $(17\times12)+(19\times1)+(14\times1)+(3\times16)=285amu$
Therefore,
$\%O=\frac{(3\times16)}{285}\times100\% =16,84\%$
