Questions: Which element in hydrochlorothiazide, C7H8ClN3O4S2, has the greatest mass percentage? A carbon B chlorine C nitrogen D oxygen

Solution Steps

First, we need to calculate the molar mass of each element in hydrochlorothiazide, \(\mathrm{C}_{7} \mathrm{H}_{8} \mathrm{ClN}_{3} \mathrm{O}_{4} \mathrm{S}_{2}\).

• Carbon (C): \(7 \times 12.01 = 84.07 \, \text{g/mol}\)
• Hydrogen (H): \(8 \times 1.008 = 8.064 \, \text{g/mol}\)
• Chlorine (Cl): \(1 \times 35.45 = 35.45 \, \text{g/mol}\)
• Nitrogen (N): \(3 \times 14.01 = 42.03 \, \text{g/mol}\)
• Oxygen (O): \(4 \times 16.00 = 64.00 \, \text{g/mol}\)
• Sulfur (S): \(2 \times 32.07 = 64.14 \, \text{g/mol}\)

Add the molar masses of all the elements to find the total molar mass of hydrochlorothiazide.

\[ \text{Total molar mass} = 84.07 + 8.064 + 35.45 + 42.03 + 64.00 + 64.14 = 297.754 \, \text{g/mol} \]

Now, calculate the mass percentage of each element using the formula:

\[ \text{Mass percentage} = \left( \frac{\text{Molar mass of element}}{\text{Total molar mass}} \right) \times 100\% \]

• Carbon: \(\left( \frac{84.07}{297.754} \right) \times 100\% = 28.24\%\)
• Hydrogen: \(\left( \frac{8.064}{297.754} \right) \times 100\% = 2.71\%\)
• Chlorine: \(\left( \frac{35.45}{297.754} \right) \times 100\% = 11.90\%\)
• Nitrogen: \(\left( \frac{42.03}{297.754} \right) \times 100\% = 14.12\%\)
• Oxygen: \(\left( \frac{64.00}{297.754} \right) \times 100\% = 21.50\%\)
• Sulfur: \(\left( \frac{64.14}{297.754} \right) \times 100\% = 21.55\%\)

Final Answer