|
|
Chemical reactions are classified into several different types. Synthesis reactions occur when two reactants combine to form one product. Decomposition reactants occur when one reactant is split to form two or more products. In a single displacement reaction one element or polyatomic ion is transferred from one reactant to the other as the reaction proceeds. In a double displacement reaction two reactants exchange parts to form two new products. Combustion reactions involve hydrocarbons with oxygen gas, normally resulting in heat, carbon dioxide and water as products. In aqueous solutions sometimes one of the products is not soluble in water, forming a precipitate. The solubility rules are used to determine when a precipitate will form. Polymerization is the formation of a long chain of molecules built from identical smaller units. 
|
|
synthesis, decomposition , single replacement, double replacement , precipitate, combustion, hydrocarbon, spectator ion, polymer, polymerization
|
|
- Synthesis reaction: A + X → AX
- Decomposition reaction: AX → A + X
- Single displacement/single replacement reaction: A + BX → B + AX
- Double displacement/double replacement reaction: AX + BY → BX + AY
- Combustion reaction: X + O2 → XO
- Combustion reaction of a hydrocarbon: CxHx → CO2 + H2O
- Polymerization reaction: [monomer + monomer]n → polymer
|
Review problems and questions |
|
- When zinc reacts with hydrochloric acid, zinc chloride and hydrogen gas are produced:
Zn + 2HCl → ZnCl2 + H2. What type of reaction is this?
 |
Single displacement/single replacement 
|
- Two reactants combine to form a single product. What type of reaction is this?
|
|
Synthesis
|
- Classify the type of reaction that occurs when silver nitrate reacts with magnesium chloride to form silver chloride and magnesium nitrate.
|
|
Double displacement/double replacement
|
- Write a balanced equation for the above reaction. Remember to criss-cross charges for ionic compounds.
|
2AgNO3 + MgCl2 → 2AgCl + Mg(NO3)2;
- Start by writing ions for each component in the reaction.
silver: Ag+; nitrate: NO3-; magnesium: Mg2+; chloride: Cl- - Next, criss-cross charges for compounds.
Silver nitrate: AgNO3; magnesium chloride: MgCl2;
silver chloride: AgCl; magnesium nitrate: Mn(NO3)2 - Write the equation.
AgNO3 + MgCl2 → AgCl + Mg(NO3)2 - Balance the equation.
2AgNO3 + MgCl2 → 2AgCl + Mg(NO3)2
|
- Use the solubility rules to identify which products, if any, will form a precipitate.
|
|
Silver chloride, AgCl, will form a precipitate. Chlorides of silver are not soluble.
|
- In a combustion reaction, if the substance is a hydrocarbon, what are the products?
|
|
The products are carbon dioxide and water.
|
- Write the balanced reaction for the combustion of octane, C8H18.
|
|
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
|
- A polymer chain is formed when a series of smaller molecules called _____ are chemically linked.
|
|
monomers
|
- In a combustion reaction, a substance reacts with oxygen. Give an example of an inorganic combustion reaction.
|
There are many correct answers to this question. Here is one: the reaction of hydrogen with oxygen to form water.
2 H2 + O2 → 2 H2O.
|
