Chemical Reactions PPT

download Chemical Reactions PPT

of 15

Transcript of Chemical Reactions PPT

  • 8/6/2019 Chemical Reactions PPT

    1/15

  • 8/6/2019 Chemical Reactions PPT

    2/15

    CHEMICAL REACTION

    A process in which one or more

    substances are changed into others.

    Chemical reactions tend to involve themotion of electrons, leading to the

    formation and breaking of chemical

    bonds.

  • 8/6/2019 Chemical Reactions PPT

    3/15

    MEANING OF A CHEMICAL

    REACTION

    Products - product is the result of a chemical

    reaction.

    Reactants - reactants are the elements or

    the compounds that enter a chemicalreaction.

  • 8/6/2019 Chemical Reactions PPT

    4/15

    TYPES OF REACTIONS

    EXOTHERMIC

    ENDOTHERMIC

    SYNTHESIS DECOMPOSITION

    SINGLEDISPLACEMENT

    DOUBLED

    ISPL

    ACE

    MENT

    COMBUSTION

  • 8/6/2019 Chemical Reactions PPT

    5/15

    EXOTHERMIC

    Many chemical reactions release energy

    in the form of heat, light, or sound.

    Exothermic reactions produce heat and

    can even be explosive.

    Na + 0.5Cl2 = NaCl

  • 8/6/2019 Chemical Reactions PPT

    6/15

    ENDOTHERMIC

    Endothermic reactions cannot occur

    spontaneously and absorb energy. .

    Work must be done in order to get these

    reactions to occur. When endothermic

    reactions absorb energy, a temperature

    drop is measured during the reaction.

    sunlight + 6CO2(g) + H2O(l) =

    C6H12O6(aq) + 6O2(g)

  • 8/6/2019 Chemical Reactions PPT

    7/15

    SYNTHESIS

    In a synthesis reaction two or morechemical species combine to form a

    more complex product.

    A + BAB

    8 Fe + S8 8 FeS

  • 8/6/2019 Chemical Reactions PPT

    8/15

    DECOMPOSITION

    In a decomposition reaction a compound

    is broken into smaller chemical species.

    ABA + B

    2 H2

    O 2 H2

    + O2

  • 8/6/2019 Chemical Reactions PPT

    9/15

    SINGLE DISPLACEMENT

    A substitution or single displacementreaction is characterized by one element

    being displaced from a compound by

    another element.

    A + BC AC + B

    Zn + 2 HClZnCl2 + H2

  • 8/6/2019 Chemical Reactions PPT

    10/15

    DOUBLE DISPLACEMENT

    In a double displacement or metathesis

    reaction two compounds exchange bonds or

    ions in order to form different compounds.

    AB + CDAD + CB

    NaCl+ AgNO3 NaNO3 + AgCl

  • 8/6/2019 Chemical Reactions PPT

    11/15

    COMBUSTION

    A reaction that involve the presence ofoxygen and releases energy. Usually ina combustion reaction oxygen combines

    with another compound to form carbondioxide and water.

    ACXHY + ((2AX +AY/2)/2)O2 (AX)CO2 +(AY/2)H2O

    C10H8 + 12 O2 10 CO2 + 4 H2O

  • 8/6/2019 Chemical Reactions PPT

    12/15

    MASS LAW

    The law of conservation of mass states

    that matter can neither be created nor

    destroyed. The mass of the reactants

    must ALWAYS equal the mass of the

    products.

  • 8/6/2019 Chemical Reactions PPT

    13/15

    PURPOSE OF BALANCING

    REACTIONS

    The equation has to be equal because

    matter can neither be created nor

    destroyed, but it can be transferred,

    which is what happens in chemical

    reactions. The amount you start with on

    the left has to be the same amount you

    end up with on the right.

  • 8/6/2019 Chemical Reactions PPT

    14/15

    EXAMPLES OF BALANCING THE

    AFOREMENTIONED REACTION

    TYPES

    3H2 + N2 2 NH3

    2C2H6 + 7O2 4CO2 + 6H2O

    4Al +3O2 2Al2O3

    2 Al + 3 CuO Al2O3 + 3 Cu

    I2 + 2 Na2S2O3 2 NaI + Na2S4O6

    K2O + H2O 2 KOH

  • 8/6/2019 Chemical Reactions PPT

    15/15

    EXAMPLES OF BALANCING THE

    AFOREMENTIONED REACTION

    TYPES

    Fe2(SO4)3 + 12 KSCN 2 K3Fe(SCN)6 + 3

    K2SO4

    (NH4)2CO3 2 NH3 + CO2 + H2O

    2 H2 + O2 2 H2O

    6 Mg + P4 2 Mg3P2 CaCl2 + 2 AgNO3 2 AgCl + Ca(NO3)2