Question

Nitrogen monoxide (NO) is a bioactive molecule in blood. Low NO concentrations cause respiratory distress and the formation of blood clots. Doctors prescribe nitroglycerin, \(\mathrm{C}_{3} \mathrm{H}_{5} \mathrm{~N}_{3} \mathrm{O}_{9}\), and isoamyl nitrate, \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{CH}_{2} \mathrm{ONO}_{2},\) to increase the blood level of NO. If each compound releases one molecule of NO per atom of \(\mathrm{N}\) it contains, calculate the mass percent of NO in each.

Short answer

The mass percent of NO is 39.65% in nitroglycerin and 22.54% in isoamyl nitrate.

Step-by-step solution

Identify the number of nitrogen atoms

Determine the number of nitrogen atoms in both nitroglycerin and isoamyl nitrate molecules. For nitroglycerin, \(\text{C}_{3} \text{H}_{5} \text{~N}_{3} \text{~O}_{9} \), there are 3 nitrogen atoms. For isoamyl nitrate, \(\text{(CH}_{3}\text{)}_{2} \text{CHCH}_{2} \text{CH}_{2} \text{ONO}_{2} \), there is 1 nitrogen atom.

Calculate molar masses

Calculate the molar masses of nitroglycerin and isoamyl nitrate based on their molecular formulas. Nitroglycerin: \[ \text{C}_{3} \text{H}_{5} \text{~N}_{3} \text{~O}_{9} = (3 \times 12.01) + (5 \times 1.01) + (3 \times 14.01) + (9 \times 16.00) = 227.09 \mathrm{g/mol} \] Isoamyl nitrate: \[ \text{(CH}_{3}\text{)}_{2} \text{CHCH}_{2} \text{CH}_{2} \text{ONO}_{2} = (5 \times 12.01) + (11 \times 1.01) + (1 \times 14.01) + (3 \times 16.00) = 133.16 \mathrm{g/mol} \]

Determine the mass percentage of NO

Calculate the mass of nitrogen monoxide (NO) released per mole of compound. For nitroglycerin: \[ 3 \times 30.01 = 90.03 \mathrm{g/mol} \] For isoamyl nitrate: \[ 1 \times 30.01 = 30.01 \mathrm{g/mol} \] The mass percent of NO is then calculated by dividing the mass of NO by the molar mass of the compound and multiplying by 100. Nitroglycerin: \[ \frac{90.03}{227.09} \times 100 \approx 39.65\text{%} \] Isoamyl nitrate: \[ \frac{30.01}{133.16} \times 100 \approx 22.54\text{%} \]

Key concepts

Nitrogen Monoxide

Nitrogen monoxide (NO) is a crucial chemical compound in the human body. It plays a vital role in various physiological processes. When there is a low concentration of NO, it can lead to respiratory issues and blood clotting. To counteract these effects, doctors sometimes prescribe compounds like nitroglycerin and isoamyl nitrate, which can release NO in the bloodstream.

Understanding the chemistry of NO is essential. NO is a simple molecule consisting of one nitrogen atom bonded to one oxygen atom. Despite its simplicity, it has significant bioactivity in the blood. It helps in the relaxation of blood vessels, thus facilitating better blood flow.

• NO is crucial for cardiovascular health.
• It helps in regulating blood pressure.
• Insufficient NO can lead to serious health issues.

Doctors utilize this knowledge to prescribe specific medications that release NO to manage various health conditions.

Molar Mass Calculation

Calculating the molar mass of a compound is a fundamental skill in chemistry. The molar mass is the weight of one mole (6.022 x 10²³ molecules) of a substance and is expressed in grams per mole (g/mol).

For instance, let’s calculate the molar masses of two important compounds: nitroglycerin and isoamyl nitrate.
Nitroglycerin (C₃H₅N₃O₉):
We sum up the atomic masses of each element in the formula:

• Carbon: 3 atoms × 12.01 g/mol = 36.03 g/mol
• Hydrogen: 5 atoms × 1.01 g/mol = 5.05 g/mol
• Nitrogen: 3 atoms × 14.01 g/mol = 42.03 g/mol
• Oxygen: 9 atoms × 16.00 g/mol = 144.00 g/mol

Total molar mass of nitroglycerin is 227.11 g/mol.

Isoamyl nitrate [(CH₃)(CH₃)CHCH₂CH₂ONO₂]:
Similar to nitroglycerin, we sum up the atomic masses:

• Carbon: 5 atoms × 12.01 g/mol = 60.05 g/mol
• Hydrogen: 11 atoms × 1.01 g/mol = 11.11 g/mol
• Nitrogen: 1 atom × 14.01 g/mol = 14.01 g/mol
• Oxygen: 3 atoms × 16.00 g/mol = 48.00 g/mol

Total molar mass of isoamyl nitrate is 133.17 g/mol.

Understanding how to calculate these values helps in many scientific applications, including determining the mass percent composition, which is crucial in this exercise.

Bioactive Molecules in Blood

Bioactive molecules are compounds that have an effect on living tissue. In the context of human physiology, these molecules include hormones, enzymes, and gases like nitrogen monoxide (NO). These molecules play significant roles in maintaining health and managing diseases.

NO is a particularly important bioactive molecule in the blood. It is involved in several key functions:

• Vasodilation: NO helps to relax the smooth muscles in blood vessels, resulting in widened vessels and improved blood flow.
• Blood pressure regulation: By influencing the dilation of blood vessels, NO helps to regulate blood pressure.
• Prevention of blood clots: NO inhibits platelet aggregation, reducing the risk of clot formation.

When NO levels are low, doctors may prescribe nitroglycerin or isoamyl nitrate, which release NO upon metabolization. These prescriptions are particularly crucial for individuals with cardiovascular issues.

Bioactive molecules like NO are of immense importance in medical science. Understanding their functions and how to manipulate their levels can lead to better therapeutic strategies and improved patient outcomes.