Percobaan Hukum Kekekalan Massa

Summary

In this video, Dewi Nurmala Sari demonstrates a simple yet effective experiment to prove Lavoisier's Law of Conservation of Mass using household items. The experiment involves a reaction between calcium carbide (CaC2) and water (H2O), producing acetylene gas (C2H2) and calcium hydroxide (Ca(OH)2). The mass of the system before and after the reaction remains unchanged, highlighting the core principle of mass conservation. The experiment also includes a visible color change in the solution, adding an educational and engaging element to the demonstration.

Takeaways

• 😀 The video demonstrates the law of conservation of mass using a simple chemistry experiment.
• 😀 The speaker uses common household items like a kitchen scale, water, plastic clip, and carbide (CaC₂) for the experiment.
• 😀 The goal of the experiment is to prove that the mass before and after the chemical reaction remains constant.
• 😀 A chemical reaction between carbide (CaC₂) and water (H₂O) produces acetylene gas (C₂H₂) and calcium hydroxide (Ca(OH)₂).
• 😀 The initial mass of water is measured at 250 grams before the reaction begins.
• 😀 The reaction produces gas bubbles, which are visible and confirm the formation of acetylene gas.
• 😀 The water's color changes from clear to pink due to the formation of calcium hydroxide (a base).
• 😀 The reaction formula is: CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂.
• 😀 Despite the visible gas production and color change, the total mass of the system remains constant, confirming the conservation of mass.
• 😀 The video ends with the speaker thanking viewers and encouraging them to like and subscribe for more educational content.

Q & A

What is Lavoisier’s Law of Conservation of Mass?

Lavoisier’s Law of Conservation of Mass states that the mass of substances before and after a chemical reaction remains constant. In other words, matter is neither created nor destroyed during the reaction.

What materials were used in the experiment to demonstrate Lavoisier’s Law?

The materials used include a kitchen scale, a glass container, plastic clips, water, carbide (CaC₂), and a pH indicator (such as phenolphthalein or a natural flower like hibiscus).

Why does the water change color during the experiment?

The water changes color because the reaction produces calcium hydroxide (Ca(OH)₂), a base that raises the pH of the water. The indicator in the water reacts to this pH change, turning the solution pink.

What chemical reaction occurs when carbide (CaC₂) reacts with water?

When carbide (CaC₂) reacts with water (H₂O), the products are acetylene gas (C₂H₂) and calcium hydroxide (Ca(OH)₂). The reaction can be written as: CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂.

What gas is produced during the reaction between carbide and water?

The gas produced is acetylene (C₂H₂), which is highly flammable and can form bubbles in the reaction.

What is the significance of using a scale in this experiment?

The scale is used to demonstrate the Law of Conservation of Mass. By measuring the mass of the system before and after the reaction, we can show that the total mass remains constant, even though the form of the matter changes.

How does the experiment prove the Law of Conservation of Mass?

The experiment proves the Law of Conservation of Mass by showing that the mass of the substances before the reaction (carbide and water) is equal to the mass of the substances after the reaction (acetylene gas and calcium hydroxide).

Why is carbide (CaC₂) used in this experiment?

Carbide (CaC₂) is used because it reacts with water to produce acetylene gas (C₂H₂), a process that is easy to demonstrate and clearly shows the mass changes involved in the reaction.

What is the role of the pH indicator in the experiment?

The pH indicator helps to visually demonstrate the formation of a base (calcium hydroxide) during the reaction. The indicator changes color, signaling a change in the pH of the water.

Can this experiment be performed with other materials to demonstrate Lavoisier’s Law?

Yes, similar experiments can be conducted with different reactants that involve measurable changes in mass. The key is to show that mass is conserved before and after the reaction.