Saturday, 30 March 2013

1.21 write word equations and balanced chemical equations to represent the reactions studied in this specification

Word equations have just the names of the reactants and products involved:
Hydrogen + Oxygen > Water
Balanced equations are the symbols of the products and reactants including the numbers of each, there must be an equal number of each element on both sides of the equation, if there are not you can alter this by putting the right number infront of a symbol:
2H + O > H2O

9 comments:

  1. Balancing Chemical Equation was Nicely Explain.......But Proper Definition is also required on chemical Equation which is given at http://www.ncerthelp.com/text.php?contype=Concept&class_id=10&sub_id=S&chapter_id=CH1&q_no=1

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  3. "2H + O > H2O"
    The actual balanced chemical for water is 2H2 + O2 > 2H2O
    This is because both hydrogen and oxygen are diatomic molecules.
    The same could be said of Carbon Dioxide: C + O2 > CO2

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  4. I really appreciate all your hard work and effort,i got my igcse exams in may and this blog got me pumped haha :L

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  5. What are the equations we need to know?

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  6. Equations are used to describe reactions.
    Word Equations
    Word equations just have the name of the reactants involved. An example is shown below:
    Hydrogen + Oxygen → Water
    Balancing Chemical equations
    Balancing chemical equations is necessary to make sure that you are following the law of conservation of mass.
    The law of conservation of mass ensures that you are not magically creating or destroying atoms.
    Here is a step by step example below:
    Al O2 → Al2 O3
    Notice how there are different number of Aluminium and Oxygen atoms on both sides.
    Balancing it will ensure that there are the same amount of atoms on both sides.
    If there is a number before the Element then it is a molecule.
    The number is subscript are atoms.
    To convert to only atoms, you have to multiply the molecules by the atoms
    Stage 1: Balance the Aluminiums
    On the left hand side we can see that there is one aluminium atom while on the right side there is 2.
    To balance this we simply put a 2 in front of the aluminium on the left hand side. Below is how it should look like.
    2 Al O2 → Al2 O3
    Stage 2: Balance the oxygens
    On the left hand side we have 2 oxygen atoms and on the right we have 3.
    If we were to go from 2 to 3 we would have to use decimals.
    For 2 to go into 3 we multiply by 1.5.
    2 Al 1.5 O2 → Al2 O3
    Ideally we don't want to leave this in decimals so we can do what we do in algebra and multiply everything out by 2.
    So:
    2 Al 1.5 O2 → Al2 O3 becomes 4 Al 3 O2 → 2 Al2O3
    As we see above there are 4 aluminium atoms on both sides and 6 oxygen atoms on both side.

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  7. Hey hannah, I just wanna say thanks so much for those amazing blogs! They really help tons!!

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  8. The Chemistry Syllabus has changed…

    Here is a New blog for the 2017 Syllabus:

    https://igcse-chemistry-2017.blogspot.hk/

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