5-4 classifying reactions

Write the formula for the following compounds:

– Potassium hydroxide• KOH

– Sulfur dioxide• SO2

– Iron (II) phosphate• Fe3(PO4)2

– Tetracarbon octahydride• C4H8

Warm-up (own paper)

5-5 Types of reactions• Objectives

– Discuss factors that affect reaction rates.– Classify chemical reactions as synthesis,

decomposition, single-replacement, double-replacement, or combustion reactions.

Reaction Rates• The speed of the reaction

• Temperature

• Surface area

• Stirring

• Concentration

Prediction Results

Fast or slow

Fast or Slow

Fast or Slow

Fast or Slow

Conservation of Mass• Mass can not be created or destroyed.

• Total number of atoms before reaction must be equal to total number after reaction.

• Atoms are rearranged in chemical reaction.

• Mass of reactants must be equal to mass of products.

Converting Mass to Moles

Converting Mass to Moles

Converting Mass to Moles

Converting Mass to Moles

Converting Mass to Moles

Converting Mass to Moles

• Each line shows the conservation of mass.

Classifying Reactions• Synthesis – combining two reactants to

make one product.– A + B AB

– 2H2 + O2 2H2O

Classifying Reactions• Decomposition – Compound breaks

down into two or more simpler substances.– AB A + B

– CaCO3 CaO + CO2

Classifying Reactions• Single replacement – one element takes

the place of another element in a compound.– A + BC B + AC

– Cu + 2AgNO3 Cu(NO3)2 + 2Ag

Activity Series• After experimentation chemists

compiled a list of elements arranged in decreasing activity.

• The element at the top of the list will replace those elements at the bottom.

Activity series of MetalsLithium (Li)Potassium (K)Calcium (Ca)Sodium (Na)Magnesium (Mg)Aluminum (Al)Zinc (Zn)

Rea

ctiv

ity D

ecre

asesIron (Fe)

Lead (Pb)Hydrogen (H)Copper (Cu)Mercury (Hg)Silver (Ag)

Classifying Reactions• Double Replacement – two different

compounds exchange positive ions and form two new compounds.– AB + CD AD + CB

– Pb(NO3)2 + 2KI PbI2 + 2KNO3

– CaCO3 + 2HCl CaCl2 + H2CO3

– H2CO3 CO2 + H2O

Combustion• A reaction in which a substance reacts

rapidly with oxygen, often producing heat and light.– CxHy + O2 CO2 + 2H2O (+ Heat + Light)

– Most combustion reactions are with carbon (organic compounds.)

– 2H2 + O2 2H2O

– Combustion of hydrogen, but also a synthesis.

5-4 Summary• What are the five types of reactions?

– Synthesis– Decomposition– Single-replacement– Double-replacement– Combustion