What are the molecular weights of the following herbicides? (b) C15H22ClNO2 (metolachlor, pre-emergent herbicide)

Verified step by step guidance

1. Identify the atomic masses of each element in the molecular formula C15H22ClNO2. You can find these values on the periodic table: Carbon (C), Hydrogen (H), Chlorine (Cl), Nitrogen (N), and Oxygen (O).
2. Multiply the atomic mass of each element by the number of atoms of that element in the molecule. For example, Carbon has an atomic mass of about 12 amu, and there are 15 Carbon atoms in the molecule, so you would calculate 15 times 12 amu for Carbon.
3. Add the total masses calculated for each element to find the total molecular weight of the compound. This involves adding the contributions from all Carbon, Hydrogen, Chlorine, Nitrogen, and Oxygen atoms.
4. Ensure the units are consistent, typically atomic mass units (amu) or grams per mole (g/mol), when adding up the individual masses.
5. The sum from the previous step will give you the molecular weight of metolachlor, C15H22ClNO2.

Key Concepts

Molecular Weight Calculation

Molecular weight, or molar mass, is the sum of the atomic weights of all atoms in a molecule. It is calculated by multiplying the number of each type of atom by its atomic weight (from the periodic table) and summing these values. For example, in C15H22ClNO2, you would calculate the contributions from carbon, hydrogen, chlorine, nitrogen, and oxygen to find the total molecular weight.

Chemical Formula Interpretation

A chemical formula provides information about the types and numbers of atoms in a molecule. In the formula C15H22ClNO2, 'C' represents carbon atoms, 'H' represents hydrogen, 'Cl' is chlorine, 'N' is nitrogen, and 'O' is oxygen. The subscripts indicate the number of each atom present, which is essential for calculating the molecular weight accurately.

Periodic Table of Elements

The periodic table is a tabular arrangement of elements, organized by increasing atomic number and grouped by similar properties. Each element has a unique atomic weight, which is crucial for calculating molecular weights. Understanding how to read the periodic table allows students to find the atomic weights needed for the molecular weight calculation of compounds like metolachlor.