Chemical Reactions and Gases

4 TYPES OF CHEMICAL REACTIONS

Synthesis ReactionDecomposition ReactionSingle Displacement ReactionDouble Displacement Reaction

SYNTHESIS REACTION = is onein which a single product is produced from two or more reactants.

X + Y XYExamples: H2 + Cl2 2HCl

S + O2 SO2

SO3 + H2O H2SO4

2NO + O2 2NO2

DECOMPOSITION REACTION = is one in which a single reactant is converted into two or more simpler substances.

XY X + YExamples: 2CuO 2Cu + O2

2H2O 2H2 + O2

CaCO3 CaO + CO2

SINGLE DISPLACEMENT REACTION = is one in which one element of a compound is replaced by another element.

X + YZ Y + XZ

Examples: Zn + H2SO4 H2 + ZnSO4

 Ni + 2HCl H2 + NiCl2

 Mg + Ni(NO3)2 Ni + Mg(NO3)2

 

DOUBLE DISPLACEMENT REACTIONS = is one in which two compounds exchange parts with each other to form two different compounds.

AX + BY AY + BXExamples: NaOH + HCl NaCl + HOH

  AgNO3 + NaCl NaNO3 + AgCl

  NaF + HCl NaCl + HF

How do you know that a chemical reaction has occurred? What should you look for?

Change in colorPrecipitate formsChange in temperature Effervescence occurs

Exothermic Chemical Reaction: Occurs when the chemical reaction releases heat. Products become warmer than the reactants.

Endothermic Chemical reaction: A chemical reaction where energy is absorbed. The products temperature is colder than the reactants.

Chemical Gases

Carbon Dioxide (CO2): A colorless odorless gas that does not aid in combustion. A burning flame will go out.

Oxygen (O2): A colorless, odorless gas that will make a flame burn brighter and faster. Has the capability of making a burning ember burst back into a flame. A gas which is required for combustion to occur.

Acetylene(C2H2): A colorless gas that will burn when oxygen is present.

Hydrogen(H2): A colorless gas that will explode in the presence of fire or a spark if oxygen is present too.