Endothermic reaction: very, VERY cool.

Summary

In this experiment, the presenter combines barium hydroxide with ammonium chloride to demonstrate an endothermic reaction. As they mix the chemicals, the reaction absorbs heat, becoming cold enough to freeze water on a wooden block. The process also releases ammonia, producing a pungent smell. The presenter notes the dramatic temperature drop, which is measured to be below zero, and observes ice crystals forming. Despite the cold, the reaction remains subtle but visually interesting, engaging viewers with its scientific and sensory effects.

Takeaways

• 🧪 The speaker is mixing barium hydroxide and ammonium chloride to demonstrate an endothermic reaction.
• 🥶 The reaction is expected to absorb heat, making it endothermic, rather than releasing heat as in an exothermic reaction.
• 🧊 The speaker wets a wooden block to show how cold the reaction will become, indicating the heat being absorbed from the environment.
• 🧉 The barium hydroxide and ammonium chloride mix together, transitioning from solid powders to a liquid state.
• 😷 The reaction releases ammonia gas, which the speaker notices by the strong, unpleasant smell.
• ❄️ As the reaction progresses, the mixture gets very cold, cold enough to freeze the water onto the bottom of the wooden block.
• 📉 The temperature drops quickly, reaching below zero degrees Celsius, as observed using a thermometer calibrated to minus 10°C.
• 🌡️ The thermometer reads minus 5°C at one point, confirming that significant heat is being absorbed by the reaction.
• ❄️ Ice crystals start forming on the sides due to the low temperature.
• 🚫 The speaker warns against touching the mixture, as it might freeze skin if touched.

Q & A

What are the two chemicals mentioned in the experiment?

The two chemicals mentioned are barium hydroxide and ammonium chloride.

What type of reaction is being demonstrated in the experiment?

The experiment is demonstrating an endothermic reaction.

Why does the speaker mention a wooden block being made wet?

The speaker wets the wooden block to show how much heat the reaction is taking in by freezing the water onto the block.

What product is formed from the reaction between barium hydroxide and ammonium chloride?

One of the products formed in the reaction is water, which causes the mixture to change consistency and become more liquid.

What gas is released during the reaction, and why does the speaker comment on its smell?

Ammonia gas is released during the reaction, and the speaker comments on its unpleasant, tangy smell.

What temperature does the reaction reach, according to the speaker?

The reaction drops below freezing, reaching around -5°C, as indicated by the thermometer.

What physical effect does the endothermic reaction have on the water at the base of the beaker?

The reaction absorbs so much heat that the water freezes and sticks to the bottom of the beaker.

Why does the speaker say that the reaction is ‘pretty cool’?

The speaker is impressed by the fact that the reaction absorbed enough heat to freeze the water at the bottom of the beaker, making the reaction visually and scientifically interesting.

What safety precautions does the speaker mention during the experiment?

The speaker mentions using hand sanitizer after chopping hearts earlier, indicating awareness of cleanliness and safety during experiments.

Why does the speaker express concern about ammonia during the experiment?

The speaker forgot that ammonia would be released, accidentally inhaling it, and commented on its strong, unpleasant smell.