Question

State the composition for a molecule of each of the following compounds: (a) cholesterol, \(\mathrm{C}_{27} \mathrm{H}_{45} \mathrm{OH}\) (b) quinine, \(\mathrm{C}_{20} \mathrm{H}_{24} \mathrm{~N}_{2} \mathrm{O}_{2}\)

Short answer

- Cholesterol: 27C, 46H, 1O (1 hydrogen from OH is included). - Quinine: 20C, 24H, 2N, 2O.

Step-by-step solution

Breakdown of Cholesterol Formula

The formula for cholesterol is \( \mathrm{C}_{27} \mathrm{H}_{45} \mathrm{OH} \). This represents one molecule of cholesterol.- \(\mathrm{C}_{27}\): 27 carbon atoms.- \(\mathrm{H}_{45}\): 45 hydrogen atoms.- \(\mathrm{O}\): 1 oxygen atom. An 'OH' group indicates the presence of a hydroxyl functional group (1 hydrogen atom is already counted as part of \(\mathrm{H}_{45}\)).

Breakdown of Quinine Formula

The formula for quinine is \( \mathrm{C}_{20} \mathrm{H}_{24} \mathrm{N}_{2} \mathrm{O}_{2} \). This represents one molecule of quinine.- \(\mathrm{C}_{20}\): 20 carbon atoms.- \(\mathrm{H}_{24}\): 24 hydrogen atoms.- \(\mathrm{N}_{2}\): 2 nitrogen atoms.- \(\mathrm{O}_{2}\): 2 oxygen atoms.

Key concepts

Chemical Formulas

Chemical formulas are a concise way to convey the elements and number of atoms present in a molecule. They are essential for identifying and distinguishing different chemical compounds. For organic molecules specifically, chemical formulas offer a shorthand notation to represent the complex structure of these compounds. Each type of atom in a molecule is represented by its elemental symbol, followed by a subscript indicating the number of atoms of that element in one molecule of the compound.

- For example: - - In cholesterol's formula, \( \mathrm{C}_{27}\mathrm{H}_{45}\mathrm{OH} \), there are 27 carbon atoms, 45 hydrogen atoms, and 1 oxygen atom. - Similarly, in quinine's formula, \( \mathrm{C}_{20} \mathrm{H}_{24} \mathrm{N}_{2}\mathrm{O}_{2} \), there are 20 carbon atoms, 24 hydrogen atoms, 2 nitrogen atoms, and 2 oxygen atoms.Understanding chemical formulas helps in predicting the properties and behaviors of molecules. It is an essential skill for anyone studying chemistry, particularly organic chemistry, as it involves the identification and classification of compounds based on their molecular composition.

Organic Chemistry

Organic chemistry is a branch of chemistry focused on the study of carbon-containing compounds. It is crucial because organic compounds make up the basis of all earthly life. In this field, we learn how atoms such as carbon (\( \mathrm{C} \)), hydrogen (\( \mathrm{H} \)), nitrogen (\( \mathrm{N} \)), and oxygen (\( \mathrm{O} \)) join to form a vast array of chemical structures.

- Key points about organic chemistry include: - Its foundation on the unique properties of carbon, which can form four covalent bonds, allowing for complex molecules. - The understanding of hydrocarbons and their derivatives which include alcohols, acids, and more.The study of organic chemistry allows chemists to predict molecular behavior in biological systems, design new synthetic materials, and come up with novel pharmaceuticals. Cholesterol and quinine are classic examples of organic compounds, each with a structure that dictates its function and interaction in biological systems.

Functional Groups

Functional groups are specific clusters of atoms within molecules that are responsible for the characteristic reactions of those molecules. Each functional group has a predictable behavior and reactivity owing to its specific atomic arrangement and bonding pattern.

- Common functional groups include: - The hydroxyl group (\( \mathrm{OH} \)) present in alcohols like cholesterol. - Amino groups (\( \mathrm{NH}_2 \)) and carbonyl groups (\( \mathrm{C}=\mathrm{O} \)) which are prevalent in bio-molecules.Functional groups help determine the physical and chemical properties of organic compounds. For instance, the hydroxyl group in cholesterol indicates that it is an alcohol and affects its solubility and reactivity. In quinine, the presence of oxygen and nitrogen highlights its complexity and the potential for hydrogen bonding and other interactions within the body. Recognizing functional groups is fundamental in organic chemistry as it makes it easier to predict reactions and formulate synthesis pathways.