Laws Of Chemical Combinations
Chapter Name : Some Basic Concepts Of Chemistry |
Sub Topic Code : 102_11_01_05_03 |
Topic Name : Laws Of Chemical Combinations |
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Sub Topic Name : Law Of Multiple Proportions |
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Introduction
John Dalton gave the Law of multiple Proportions which states two or more elements can combine to form different compounds in smallest whole-number ratios.
Pre-Requisites:
Atom, compound, element, proportion
Activity:
H2O and H2O2 (sometimes used as a disinfectant) both are compounds having H and O but in different whole number ratio.
Real Life Question:
How can H and O combine to form more than one compound?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Law of definite proportion | Two or more elements can combine to form different compounds in smallest whole-number ratios. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Water and Peroxide | Look at how both are made of Hydrogen and Oxygen you can drink water but not peroxide. |
Real life uses :
Water (H2O) is used for drinking but peroxide is not. It has a different use (cleaning wounds)
Places to visit :
Chemist: get a bottle of peroxide and check out its usage and chemical formula. Compare it with water. Garage: Exhaust pipe of car emits Nitrogen monoxide which combines with atmospheric oxygen to make NO2 which is a major air pollutant. Both are composed of the same elements N and O but in different ratios.
Practical examples around us
| Examples | Explainations |
|---|---|
| Car exhaust fumes | Fumes emit NO gas which later combines with air to form NO2 which pollutes the air. |
What you learn in Theory:
Different compounds are formed from the same elements, just having different ratios of the elements.
What you learn in Practice:
Different compounds in nature or made artificially can have the same elements but I different ratios. Ex. H2O is water but H2O2 is hydrogen peroxide.