Ethylic alcohol (part 1) - Natural Science 9

Ethanol (Ethyl Alcohol) Structure and Properties
📌 The molecular formula for Ethyl Alcohol (Ethanol) is C₂H₆O, and its condensed structural formula is CH₃CH₂OH.
🔥 The characteristic properties of ethanol are attributed to the presence of the hydroxyl functional group (–OH) within its structure.
💧 Ethanol is a colorless liquid with a characteristic odor, a pungent taste, and is infinitely miscible (soluble) in water.
🌡️ Key physical constants include a boiling point of 78.3°C and a density of 0.789 g/mL measured at 20°C.

Alcohol Content Measurement and Applications
🔢 Alcohol Degree (ABV) is defined as the volume (in mL) of pure ethanol present in 100 mL of solution at 20°C, often symbolized as x° or x% v/v.
🧼 Ethanol is a primary component in medical alcohol and hand sanitizers, typically present at concentrations ranging from 60% to 85% by volume.
🦠 Ethanol kills bacteria by causing protein coagulation and destroying their structure upon contact.

Chemical Reactions and Safety
🔥 Ethanol undergoes combustion in the air, producing carbon dioxide ($CO_2$), water vapor ($H_2O$), and releasing significant heat, indicated by a blue flame.
⛽ The combustion reaction is represented by the equation: $C_2H_6O + 3O_2 \rightarrow 2CO_2 + 3H_2O$.
💡 Ethanol is used as fuel in alcohol lamps and internal combustion engines because it is easily flammable and releases substantial heat upon burning.
⚠️ Essential safety precautions include storing ethanol in a well-ventilated area, keeping it away from heat sources, and never using matches or lighters near it due to its flammability.

Key Points & Insights
➡️ The presence of the –OH group is responsible for ethanol's distinct chemical properties compared to hydrocarbons.
➡️ 70° alcohol means that 100 mL of the solution contains 70 mL of pure ethanol (at 20°C).
➡️ Ethanol's disinfecting power stems from its ability to denature microbial proteins.
➡️ Store flammable liquids like ethanol in a ventilated area, away from ignition sources, due to its easy flammability and high heat release upon combustion.

📸 Video summarized with SummaryTube.com on Feb 04, 2026, 15:37 UTC