Fessy Physical Science 7.2 Types of Reactions
What is a combustion reaction?
A combustion reaction is one in which a substance reacts rapidly with oxygen, often producing heat and light. The burning of natural gas is an example of combustion.
What is a decomposition reaction?
A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances. The reactant in a decomposition reaction must be a compound. The products may be elements or compounds. The general equation for a decomposition reaction is AB >>A + B
What is a double-replacement reaction?
A double-replacement reaction is one in which two different compounds exchange positive ions and form two new compounds. The general form of a double replacement reaction is AB + CD >> AD + CB (Note: that two replacements take place in this reaction. Not only is A replacing C, but C is also replacing A.)
What is a single-replacement reaction?
A single-replacement reaction is a reaction in which one element takes the place of another element in a compound. Single-replacement reactions have the general form A+ BC >>B + AC
What is a synthesis reaction?
A synthesis reaction is a reaction in which two or more substances react to form a single substance. The reactants may be either elements or compounds. The product synthesized is always a compound. The general equation for a synthesis reaction is A + B >> AB
What is oxidation?
Any process in which an element loses electrons during a chemical reaction is called oxidation. A reactant is oxidized if it loses electrons. Note that the modern definition of oxidation is much broader than the original meaning. Oxygen doesn't always have to be present in order for an element to lose electrons.
Explain the difference between a single- replacement reaction and a double-replacement reaction.
In a single-replacement reaction, an element replaces another element in one compound. In a double-replacement reaction, two elements replace each other in two different compounds.
The synthesis of water is described by the equation 2H2 + O2>> 2H2O. How is the decomposition of water related to this reaction? Explain, using a chemical equation.
In the reaction 2H2 + O2 >> 2H2O, water is formed from its elements. During the decomposition of water, water is broken down into its elements, according to the equation 2H2O >> 2H2 + O2.
What is a oxidation-reduction reaction?
Oxidation and reduction always occur together. When one element loses electrons, another element must gain electrons. Note that oxidation-reduction reactions do not always involve complete transfers of electrons. For example, in the synthesis of water, hydrogen is oxidized as it partially loses electrons. Oxygen is reduced as it partially gains electrons.
What are the Four general types of chemical reactions?
Some general types of chemical reactions are synthesis reactions, decomposition reactions, Replacement reactions:(single-replacement reactions, double-replacement reactions), and combustion reactions. Each type describes a different way in which reactants interact to form products.
How did the discovery of subatomic particles affect the classification of reactions?
The discovery of subatomic particles allowed scientists to classify certain reactions as transfers of electrons between atoms.
What is reduction ?
The process in which an element gains electrons during a chemical reaction is called reduction. A reactant is said to be reduced if it gains electrons.
Is the reaction represented by the following equation a redox reaction? Explain your answer. 2Hg + O2>> 2HgO
Yes, this is a redox reaction because electron transfer takes place. The charge of mercury changes from 0 to 2 (oxidation). The charge of oxygen changes from 0 to 2 (reduction).
8. Identify these reactions as synthesis, decomposition, single replacement, double replacement, or combustion. a. Pb(NO3)2 + 2HCl >> PbCl2 + 2HNO3 b. 2C2H6+ 7O2 >> 4CO2 + 6H2O c. Ca + 2HCl >> CaCl2 + H2 d. 2SO2 + O2 >> 2SO3
a. Double replacement b. Combustion c. Single replacement d. Synthesis
