Chemistry Heat Part 7 (Mercury In Thermometer) Class 7 VII

TL;DR

Mercury is used in thermometers due to its liquid state at room temperature, high coefficient of expansion, non-stick property, shiny appearance, low melting point, and high boiling point. However, its toxicity has led to the use of alcohol as a substitute.

Transcript

hello friends this video on heat pack 7 is brought to you by exam floor comm no more fear from exam now we looked at both clinical as well as laboratory thermometers everywhere we see that now it is always a Chosen mercury which is used as the liquid inside the thermometer now what is so special in mercury that it is in demand for making thermomete... Read More

Key Insights

• 🤒 Mercury is chosen for thermometers due to its liquid state and ability to flow through the thermometer.
• 🙂 High coefficient of expansion in mercury enables accurate temperature readings with slight heat changes.
• 🤒 Non-stick property of mercury allows it to flow smoothly along the length of the thermometer.
• 🫠 The shiny appearance of mercury makes it easier to read the temperature.
• 🫠 Mercury's low melting point and high boiling point prevent premature melting or boiling.
• 🤒 Despite its advantages, mercury is being replaced in thermometers due to its toxicity and disposal challenges.
• 🤒 Alcohol is a common substitute for mercury in thermometers, offering similar properties and non-toxicity.

Questions & Answers

Q: Why is mercury used in thermometers?

Mercury is a liquid at room temperature, allowing it to flow through the thermometer. It also has a high coefficient of expansion, ensuring noticeable expansion with slight heat, and does not stick to the walls of the thermometer.

Q: What are the advantages of using mercury in thermometers?

Mercury's advantages in thermometers include its fluidity, high coefficient of expansion for accurate temperature readings, non-stick property for smooth flow, shiny appearance for easy reading, low melting point, and high boiling point.

Q: Why is mercury being phased out in thermometers?

Mercury is being phased out due to its toxicity and difficulties in disposal if a thermometer breaks. Substitute substances like alcohol have been found, which are non-toxic and have similar properties, such as a high coefficient of expansion.

Q: What are the advantages of using alcohol in thermometers?

Alcohol is a substitute for mercury in thermometers due to its non-toxic nature and ease of disposal. It also has a high coefficient of expansion and can provide accurate temperature readings.

Summary & Key Takeaways

• Mercury is chosen as the liquid in thermometers because it is a fluid that can move through the tube, unlike solids.

• Mercury has a high coefficient of expansion, meaning it expands noticeably even with slight heat, allowing for accurate temperature readings.

• Its non-stick property ensures that it can flow along the length of the thermometer, and its shiny appearance makes it easier to read.