Calculate the percentage by mass of the indicated element in the following compounds: (d) nitrogen in epinephrine, C9H13NO3 , also known as adrenalin, a hormone that is important for the fightor- flight response

Verified step by step guidance

1. Step 1: First, we need to calculate the molar mass of epinephrine (C9H13NO3). The molar mass of a compound is calculated by adding up the molar masses of each element in the compound. The molar mass of carbon (C) is approximately 12.01 g/mol, hydrogen (H) is approximately 1.01 g/mol, nitrogen (N) is approximately 14.01 g/mol, and oxygen (O) is approximately 16.00 g/mol.
2. Step 2: Multiply the molar mass of each element by the number of atoms of that element in the compound. For epinephrine, this would be (9 atoms C * 12.01 g/mol C) + (13 atoms H * 1.01 g/mol H) + (1 atom N * 14.01 g/mol N) + (3 atoms O * 16.00 g/mol O).
3. Step 3: Now, we need to calculate the mass contribution of nitrogen to the compound. This is done by multiplying the molar mass of nitrogen by the number of nitrogen atoms in the compound, which is (1 atom N * 14.01 g/mol N).
4. Step 4: To find the percentage by mass of nitrogen in the compound, divide the mass contribution of nitrogen by the total molar mass of the compound, and then multiply by 100 to convert the decimal to a percentage.
5. Step 5: The result is the percentage by mass of nitrogen in epinephrine.

Key Concepts

Molar Mass Calculation

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). To calculate the molar mass of a compound, you sum the atomic masses of all the atoms in its molecular formula. For epinephrine (C9H13NO3), you would calculate the total mass by multiplying the number of each type of atom by its respective atomic mass and adding these values together.

Percentage by Mass

Percentage by mass is a way to express the concentration of an element within a compound. It is calculated by dividing the mass of the specific element in one mole of the compound by the total molar mass of the compound, then multiplying by 100. This gives a clear representation of how much of the compound's mass is contributed by the element of interest.

Elemental Composition

Elemental composition refers to the types and amounts of elements present in a compound. In the case of epinephrine, understanding its elemental composition (carbon, hydrogen, nitrogen, and oxygen) is crucial for calculating the percentage by mass of nitrogen. Each element's contribution to the overall mass of the compound must be considered to accurately determine the desired percentage.