AHA! Chemistry with Prof Bob
  • Home
  • Modules
    • 02 The nature of matter >
      • 0201 Atoms: Building blocks
      • 0202 Classification of matter
    • 05 Chemical reaction, chemical equations >
      • 0500 Overview, preview
      • 0501 Amount of substance, mole
      • 0502 Avogadro constant: How many?
      • 0503 Avogadro constant: Why that number?
      • 0504 Chemical formulas: What do they mean?
      • 0505 What can equations tell us?
      • 0506 Limiting reactants
    • 09 Solutions >
      • 0901 What is a solution?
      • 0902 Miscibility of liquids
      • 0903 Like dissolves like?
      • 0905 Dissolution of ionic salts in water
      • 0906 Can we predict solubilities of salts?
      • 0907 Solution concentration
      • 0908 Chemical species, speciation
      • 0909 Solutes: Electrolytes or non-electrolytes?
      • 0910 Electrolytes - strong or weak?
      • 0911 Concentrated, dilute, strong, weak
      • 0912 Species concentration vs. solution concentration
      • 0913 Weak electrolytes: Getting quantitative
    • 11 Dynamic chemical equilibrium >
      • 1100 Equilibrium: An overview
      • 1101 Visualising dynamic equilibrium
      • 1102 The jargon of equilibrium
      • 1103 Equilibrium constants
    • 22 Evidence from spectroscopy >
      • 2200 Overview, preview
      • 2201 Spectroscopy: Quantization of energies
      • 2202 Light: Wave-particle "duality"
      • 2203 UV-Visible spectroscopy
      • 2204 Beer's law
    • 27 Communicating chemistry >
      • 2700 Overview, preview
      • 2703 The jargon we use
  • TOC
  • Index
  • Teachers' area
    • T01 Communicating chemistry
    • T02 Beer's law
    • T03 Professional amnesia of the chemistry teaching professio
    • T04 Law of equilibrium
    • T05 Visusalizing dynamic chemical equilibrium
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​0500 chemical reactions and equations: 
Overview, preview

Chemical reactions are real phenomena - often able to be seen or heard.

They include the burning of natural gas, the main component of which is methane - as pictured in the banner photo above.

And the electron-transfer processes that occur in batteries when they are providing us with energy, or when they are being re-charged.

And the oxidation-reduction life process of respiration, as well as of decomposition of dead matter, once living.

And the precipitation of limestone in caves.

And the reaction of carbon dioxide from the atmosphere in the upper layers of the ocean, making the water more acidic that it would otherwise be.
​
Chemical equations, on the other hand, are a form of communication about chemical reactions. 

We use chemical equations to communicate information about chemical reactions. Some of this information is in response to qualitative questions like "What are the reactants?" and "What are the products?"


And if we have the appropriate balanced equation, we can find answers to quantitative questions like "How much of this reacts with how much of that?" and "How much of this product will be formed?"

In working with equations, questions of "How much?" are answered in terms of chemical amount (unit of measurement, the mole) so this way of measuring quantities needs to be understood to interpret chemical equations. Prof Bob discusses this link between mass of  a substance and the number of atoms, molecules, or ions in Module 0501: Chemical amount, and its unit of measurement, mole.


The number of particles in 1 mol of any substance (called the Avogadro constant) is astonishingly large, and almost too big a number to comprehend. Prof Bob tackles this challenge in Module 0502: The Avogadro constant: How many particles is that?
​
And why is the Avogadro constant the particular number that it is? Is it a universal constant? Or a random choice? See Module 0503: The Avogadro constant: Why is it that number?
​
To interpret correctly the meaning of the chemical formula of a substance, we need to know about the structure of the substance at the sub-microscopic level. In particular, how we interpret the formula of a substance characterized as an ionic compound is different from how we interpret the formula of a compound categorized as a covalent molecular compound. Prof Bob discusses this difference in Module 0504: Chemical formulas: How do we interpret them?
​

Balanced chemical equations are very powerful descriptions of chemical reactions, but sometimes people attribute more meaning to them than the information that they carry. The information that they do carry is extraordinarily important, and is the basis of all quantitative calculations. See Module 0505: Balanced chemical equations: What can they tell us?

If we mix some substances that react with each other, how much of the products can be formed? What decides the maximum amount of product that can be formed from the added amounts of the reactants? Aussie works his way through this issue with Prof Bob in Module 0506: Limiting reactants: What limits how much reaction can happen?
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Seek knowledge and wisdom, and enjoyment will follow
Prof Bob (2018)
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  • Home
  • Modules
    • 02 The nature of matter >
      • 0201 Atoms: Building blocks
      • 0202 Classification of matter
    • 05 Chemical reaction, chemical equations >
      • 0500 Overview, preview
      • 0501 Amount of substance, mole
      • 0502 Avogadro constant: How many?
      • 0503 Avogadro constant: Why that number?
      • 0504 Chemical formulas: What do they mean?
      • 0505 What can equations tell us?
      • 0506 Limiting reactants
    • 09 Solutions >
      • 0901 What is a solution?
      • 0902 Miscibility of liquids
      • 0903 Like dissolves like?
      • 0905 Dissolution of ionic salts in water
      • 0906 Can we predict solubilities of salts?
      • 0907 Solution concentration
      • 0908 Chemical species, speciation
      • 0909 Solutes: Electrolytes or non-electrolytes?
      • 0910 Electrolytes - strong or weak?
      • 0911 Concentrated, dilute, strong, weak
      • 0912 Species concentration vs. solution concentration
      • 0913 Weak electrolytes: Getting quantitative
    • 11 Dynamic chemical equilibrium >
      • 1100 Equilibrium: An overview
      • 1101 Visualising dynamic equilibrium
      • 1102 The jargon of equilibrium
      • 1103 Equilibrium constants
    • 22 Evidence from spectroscopy >
      • 2200 Overview, preview
      • 2201 Spectroscopy: Quantization of energies
      • 2202 Light: Wave-particle "duality"
      • 2203 UV-Visible spectroscopy
      • 2204 Beer's law
    • 27 Communicating chemistry >
      • 2700 Overview, preview
      • 2703 The jargon we use
  • TOC
  • Index
  • Teachers' area
    • T01 Communicating chemistry
    • T02 Beer's law
    • T03 Professional amnesia of the chemistry teaching professio
    • T04 Law of equilibrium
    • T05 Visusalizing dynamic chemical equilibrium
  • Aha! Whatever
    • Playful dolphins
    • The University of Western Australia
    • Kings Park
  • Prof Bob?
    • Family
    • Travel
    • Perth
    • At work
  • Travelling
  • Contact
  • Blog
  • In four days for two days