Laws Of Chemical Combinations
Chapter Name : Some Basic Concepts Of Chemistry |
Sub Topic Code : 102_11_01_05_05 |
Topic Name : Laws Of Chemical Combinations |
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Sub Topic Name : Avogadro's Law |
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Introduction
Avogadro's law is a gas law which states that, under constant temperature (T) and pressure (P), equal volumes of all gases contain the same number of molecules. Therefore 1 mole of a gas would have a volume of 22.4 L and 6.02 X 1023 molecules at same conditions of T and P temperature and pressure(T and P) There is a direct relationship between volume and the number of moles of a gas at constant T and P.
Pre-Requisites:
Mole, gas, volume, Direct relationship
Activity:
A helium balloon fully inflated stays up in the air than one which has less helium gas in it.
Real Life Question:
Does a small balloon contain more molecules of a gas or a bigger one at the same pressure and temperature?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Avogadro’s law | Avogadro's law is a gas law which states that, under constant temperature (T) and pressure (P), equal volumes of all gases contain the same number of molecules. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Balloon | Take a balloon and observe its size once you deflate it a bit or inflate it. What happens to the volume of the balloon and the gas in it? |
Real life uses :
Inflating a balloon
Places to visit :
At home, try to inflate a balloon and notice the volume change.
Practical examples around us
| Examples | Explainations |
|---|---|
| Any container with a movable lid and a connecting pipe to pump gas in and out | If you pump in more gas into the container the lid moves up, and volume increasing. If you pull some gas out the lid comes down and volume decreases. As volume increases so does the number of moles of the gas and vice versa. |
What you learn in Theory:
The volume of a gas is directly proportional to the number of moles of the gas at constant temperature and pressure. At the same T and P, equal volumes of all gases contain the same number of moles/ molecules.
What you learn in Practice:
As the volume of a container filled with gas increases (balloon or container with a movable lid) so does the number of moles of the gas in the container.