Question

question 9
1 pts
aspirin, also known as acetylsalicylic acid (c₉h₈o₄), is a drug often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti - inflammatory medication. how many grams of oxygen are in a 21.2 g sample of acetylsalicylic acid? report your answer to 2 decimal places and do not include units in your answer.

Explanation:

Step1: Calculate molar mass of \(C_9H_8O_4\)

Molar mass of \(C = 12.01\space g/mol\), \(H= 1.008\space g/mol\), \(O = 16.00\space g/mol\)
\(M = 9\times12.01+8\times1.008 + 4\times16.00\)
\(M=108.09+8.064 + 64.00\)
\(M = 180.154\space g/mol\)

Step2: Find mass fraction of \(O\)

Mass of \(O\) in one mole of \(C_9H_8O_4\): \(m_O=4\times16.00 = 64.00\space g\)
Mass fraction of \(O\): \(\omega=\frac{64.00}{180.154}\)

Step3: Calculate mass of \(O\) in \(21.2\space g\) sample

\(m = 21.2\times\frac{64.00}{180.154}\)
\(m=\frac{21.2\times64.00}{180.154}\)
\(m=\frac{1356.8}{180.154}\approx7.53\)

Answer:

\(7.53\)