Problem 70 - General Chemistry

Question

Identify each of the following compounds. a. An acidic compound that also has properties of an aldehyde; its molecular formula is \(\mathrm{CH}_{2} \mathrm{O}_{2}\). b. A compound used as a preservative for biological specimens and as a raw material for plastics. c. A saturated hydrocarbon boiling at \(0^{\circ} \mathrm{C}\) that is liquefied and sold in cylinders as a fuel. d. A saturated hydrocarbon that is the main constituent of natural gas.

Step-by-Step Solution

Answer

a. Formic acid; b. Formaldehyde; c. Propane; d. Methane.

Step 1: Analyze Compound A

The given compound is an acidic compound with properties of an aldehyde and a molecular formula of \(\mathrm{CH}_2\mathrm{O}_2\). This suggests it contains both an aldehyde group (\(-CHO\)) and acidity likely from a carboxyl group. The compound that matches these characteristics is formic acid, which is also known as methanoic acid.

Step 2: Analyze Compound B

The compound used as a preservative for biological specimens and as a raw material for plastics is formaldehyde. Formaldehyde is extensively used in the production of resins and as an embalming agent in biological specimen preservation.

Step 3: Analyze Compound C

A saturated hydrocarbon boiling at \(0^{\circ}\mathrm{C}\) and sold as fuel is likely referring to propane. Propane is a three-carbon alkane (\(\mathrm{C}_3\mathrm{H}_8\)), which is gaseous at room temperature but liquefied under pressure for use as fuel.

Step 4: Analyze Compound D

The main constituent of natural gas that is a saturated hydrocarbon is methane. Methane (\(\mathrm{CH}_4\)) is the simplest alkane and the primary component of natural gas.

Key Concepts

Aldehydes

Aldehydes are organic compounds that have a specific functional group denoted by egin{math} -CHO ext{ (a carbon atom double-bonded to oxygen and single-bonded to hydrogen)} . They play a crucial role in organic chemistry due to their wide range of chemical reactions. . Aldehydes are typically obtained through the oxidation of primary alcohols. . They have a characteristic pungent smell and are highly reactive.

• Some aldehydes like formaldehyde are used in preservation and manufacturing materials like resins.
• They can also be part of more complex molecules, affecting their reactivity and applications.

Aldehydes are essential in both biochemical pathways and industrial processes, making them a key topic in organic chemistry.

Hydrocarbons

Hydrocarbons are compounds made entirely of hydrogen and carbon atoms . They form the foundation for organic chemistry and are categorized mainly into two types: saturated and unsaturated hydrocarbons . Saturated hydrocarbons, or alkanes, have single bonds between carbon atoms. . These can be linear or branched and are generally less reactive than unsaturated hydrocarbons.

• Alkanes like methane and propane are common fuels.
• These hydrocarbons are used extensively in the energy sector and as starting materials for other chemicals.

Understanding hydrocarbons is crucial for studying more complex organic structures and their transformations.

Natural Gas

Natural gas is a vital source of energy composed primarily of methane (about 70-90%) . Methane, egin{math} ext{CH}_4 ext{, is a simple alkane with one carbon atom bonded to four hydrogen atoms} . It is an efficient fuel source because it burns cleaner than other fossil fuels . Liquified natural gas (LNG) is blazingly popular for its convenience in transportation and storage.

• Natural gas is extracted from underground reservoirs and is used for electricity generation, heating, and industrial processes.
• The process is considered more environmentally friendly compared to oil and coal.

Given its abundance and cleaner burning properties, natural gas plays a significant role in the transition to sustainable energy sources.

Acids

Acids are substances that can donate a proton to other compounds, known as bases. . In the realm of organic chemistry, carboxylic acids are particularly important. . Their functional group is egin{math} -COOH ext{, consisting of a carbonyl and a hydroxyl group attached to the same carbon atom} . One unique example of an organic acid with aldehyde properties is formic acid . Formic acid is both the simplest carboxylic acid and the first member of the aldehyde functional group family due to its chemical structure containing a egin{math} -CHO ext{ group} . This duality offers an interesting convergence of reactivity properties.

• Organic acids are often used in food industry, pharmaceuticals, and as preservatives.
• They are also significant in their role within metabolic processes in living organisms.

Understanding organic acids and their interplay of properties aids in the comprehension of broader chemical reactions and applications in daily life.