ORGANIC LAB MIDTERM

• Methane is First in the series of Parrafin/Alkane (which is saturated)
• The simplest alkane and the primary component of natural gas.
• Methane color is colorless, often referred to as marsh gas or natural gas
• abundant hydrocarbon is a greenhouse gas, contributing to climate change
• Saturated - single bond and occupied valence
• DECOMPOSITION REACTION- type of chemical reaction in which a single compound breaks down into two or more simpler substances. This process occurs when the original compound is subjected to heat, light, electricity, or other forms of energy
• CH3COONa - Sodium acetate
• CaO - calcium oxide
• NaOH - sodium hydroxide
• Calcium oxide + Sodium Hydroxide - Soda Lime
• Product: Ch4 (Methane) and Na2CO3 (Sodium Carbonate) Biproduct: H2O
• Reactants: Anhydrous Sodium Acetate
• Anhydrous Sodium Acetate: serves as the source of acetate ions (CH3COO-) in the reaction.
• When heated, anhydrous sodium acetate decomposes to release acetate ions, which subsequently react with the components of soda lime to produce methane.
• Soda Lime - a mixture of sodium hydroxide (NaOH) and calcium oxide (CaO), acts as a strong base and dehydrating agent in the reaction.
• Strong Base: NaOH
• Dehydrating agent: Calcium Oxide
• Dehydration: Removing of water
• The sodium hydroxide component of soda lime reacts with anhydrous sodium acetate to form sodium carbonate (Na2CO3) and water vapor (H2O).
• The calcium oxide component helps in the dehydration of the reaction mixture, facilitating the elimination of water molecules.
• Overall, soda lime promotes the decomposition of anhydrous sodium acetate and facilitates the formation of methane gas.
• The dry ignition tube is a glass tube typically made of borosilicate glass, resistant to high temperatures. It provides a controlled environment for the chemical reaction to occur. The tube is dry to prevent any moisture from interfering with the reaction.
• A Bunsen burner, is used to apply heat to the reaction mixture inside the ignition tube. The burner provides a controlled flame that allows for precise heating of the reagents.
• Reagents: The main reagents used in the synthesis of methane are anhydrous sodium acetate and soda lime. Anhydrous sodium acetate serves as the source of acetate ions, while soda lime acts as a strong base and dehydrating agent, facilitating the reaction.
• Reaction with Alcoholic Iodine: The absence of color change indicates the lack of unsaturation in methane. A color change would suggest the presence of unsaturated compounds.
• Reaction with Alkaline KMnO₄: The lack of reaction with alkaline KMnO₄ further confirms the absence of unsaturation in methane. Any observed color changes would indicate the presence of unsaturated impurities.
• The combustion of methane produces a clean, blue flame, indicating complete combustion to carbon dioxide and water. Any deviation from this observation may suggest impurities affecting the combustion process.
• Any discrepancies observed in the chemical tests could be attributed to impurities present in the synthesized methane. Common impurities may include ethylene, ethane, or other hydrocarbons with unsaturated bonds.
• The presence of impurities can affect the physical and chemical properties of methane, such as its reactivity with bromine and alkaline KMnO₄.
• Further purification techniques, such as fractional distillation or gas chromatography, may be required to isolate pure methane for specific applications.