PENENTUAN ENTALPI REAKSI DENGAN KALORIMETER

Summary

In this video, Utin explains how to determine the enthalpy change (ΔH) of reactions using a calorimeter. The process involves calculating heat absorbed by water during a reaction using the formula Q = m × c × ΔT. Through two examples—one involving the dissolution of NaOH and another with the neutralization of NaOH and HCl—viewers learn how to calculate ΔH in kJ/mol. The video emphasizes key concepts such as exothermic and endothermic reactions, unit conversions, and interpreting temperature changes to identify the reaction type. It’s an engaging and informative guide for students learning thermochemistry.

Takeaways

• 😀 The video teaches how to determine the enthalpy change (ΔH) of reactions using a calorimeter.
• 😀 A fundamental formula for calculating heat is introduced: Q = m * c * ΔT, where Q is heat, m is mass, c is specific heat, and ΔT is temperature change.
• 😀 In a calorimeter experiment, the heat released or absorbed by the reaction (system) equals the heat gained or lost by the water and calorimeter.
• 😀 The unit of heat (Q) can be in calories, kilojoules, or kcal, depending on the context.
• 😀 The mass (m) in the formula refers to the mass of the substance involved, typically measured in grams.
• 😀 Specific heat (c) refers to the heat capacity of the substance (water or solution), which can vary depending on the solution being used.
• 😀 In an exothermic reaction, the temperature of the solution increases, indicating that heat is released by the reaction.
• 😀 An example of using the formula is calculating the enthalpy change of dissolving NaOH in water, where the temperature increase indicates an exothermic process.
• 😀 The video provides two examples of enthalpy change calculations, one for dissolving NaOH and one for a neutralization reaction between NaOH and HCl.
• 😀 For neutralization reactions, the temperature increase suggests that the process is exothermic, and the enthalpy change can be calculated using the same formula.
• 😀 The video also includes a practice problem where viewers can apply the learned concepts to calculate the enthalpy change of a neutralization reaction between NaOH and HCl.

Q & A

What is the primary focus of the video tutorial?

The primary focus of the video is teaching how to determine the enthalpy change (ΔH) of a reaction using a calorimeter, including practical examples such as the dissolution of NaOH and neutralization reactions.

How is enthalpy change (ΔH) calculated in the script?

Enthalpy change (ΔH) is calculated using the formula Q = m * c * ΔT, where Q is the heat absorbed or released, m is the mass in grams, c is the specific heat capacity, and ΔT is the temperature change.

Why is the heat released during a reaction important in determining ΔH?

The heat released or absorbed during a reaction helps determine whether the reaction is exothermic or endothermic, and it is crucial for calculating the enthalpy change, as it reflects the system’s heat exchange.

What is the significance of the temperature change (ΔT) in the calculation of ΔH?

The temperature change (ΔT) represents the difference in temperature before and after the reaction. It helps in determining the amount of heat absorbed or released by the system, which is essential for calculating the enthalpy change (ΔH).

How do you interpret the sign of ΔH from the temperature change in an experiment?

If the temperature increases during the reaction, the reaction is exothermic, and ΔH will be negative. If the temperature decreases, the reaction is endothermic, and ΔH will be positive.

What is the role of the calorimeter in the experiment?

The calorimeter is used to measure the heat absorbed by the solution or the system during the reaction. It helps in calculating the heat change (Q) by monitoring the temperature change of the surrounding medium (usually water).

How is the mass (m) of the system determined in the calculation?

The mass (m) is typically the mass of the solvent or the solution involved in the reaction. For example, if 50 mL of water is used, its mass is considered to be 50 grams because the density of water is approximately 1 g/mL.

In the example with NaOH, what information is given to calculate ΔH?

In the example, the mass of NaOH is given as 2 grams, the volume of water is 50 mL, the temperature change (ΔT) is from 27°C to 32°C, and the specific heat capacity of the solution is 4.25 J/g·K. These values are used to calculate ΔH.

What is the final unit of ΔH after the calculation in the example?

The final unit of ΔH is kilojoules per mole (kJ/mol), which is derived from the heat change (Q) in joules, divided by the number of moles of the substance involved in the reaction.

Why is it important to use the correct formula when calculating ΔH?

Using the correct formula ensures accurate calculations of the heat exchange during a reaction, which directly influences the determination of enthalpy change (ΔH). It is essential for understanding whether a reaction absorbs or releases heat and for comparing different reactions.