Combination (or synthesis) reactions are reactions that form a single product from two or more substances (elements or compounds).

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1 (or synthesis) reactions are reactions that form a single product from two or more substances (elements or compounds). Concept Definition Study the primary definition of this concept, broken into general, basic, and advanced English definitions. Also see the mathematical definition and any requisite background information, such as conditions or previous definitions. Basic (or synthesis) reactions are reactions that form a single product from two or more substances (elements or compounds). Common types of reactions that fall under this category include: 1. The reaction between metallic elements and nonmetallic elements to form an ionic compound. In this type of reaction, metals will lose electrons and become cations (ions that are positively charged) and nonmetals will gain electrons and become anions (ions that are negatively charged). 2. The reaction between two different nonmetallic elements to form a covalent compound. The formula of the product can be predicted since the more reactive nonmetal will reach a negative common oxidation number, and the less reactive nonmetal will reach a positive common oxidation number. 3. The reaction between a compound and an element to form a new compound (given that there exists a higher possible positive oxidation number(s) for an element in the original compound). After the reaction, the element with a positive partial charge will have a higher 1 / 5

2 oxidation number. 4. The reaction between two compounds to form a new compound. Real World Application Discover processes or disciplines in the natural or man-made worlds that employ the concept. In chemical industry, the famous reaction of hydrogen gas and chlorine gas is applied in making hydrochloric acid. H 2 + Cl 2 2HCl The rusting of iron can also be categorized as combination reaction. It is actually a very complicated reaction of iron, oxygen and water forming iron rust. Burning of coal : C + O 2 CO 2 Discharging of a battery is usually a combination reaction. For example, oxyhydrogen fuel cell: 2H 2 + O 2 2H 2 O 2 / 5

3 Vocabulary Learn important vocabulary for this concept, including words that might appear in assessments (tests, quizzes, homework, etc.) that indicate the use of this concept. Important Vocabulary Term Context Anion - Na + (aq) is the cation and Cl - (a Cation - Na + (aq) is the cation and Cl - (a (Synthesis) reactions - NaO and H 2 O react in a combination reaction. Oxidation Number - Determine the oxidation 4 numbers of each element. (Ans: in BaSO Ba: +2; S: +6; O: -2) Videos Browse relevant videos from the Journal of Chemical Education's (JCE) Chemistry Comes Alive! library and other video sources. Hydrogen + Chlorine Cannon Hydrogen + Chlorine Cannon (Animation) Iron with Sulfur Sodium with Chlorine Potassium with Bromine 3 / 5

4 Computer Animations Experience computer simulators or animations that illustrate the concept discussed here. Many simulators or animations come with worksheets for use in class. Classroom Demonstations Investigate lab procedures suitable for live classroom demonstrations or guided student exploration. Demos Burning Iron Summary Read a summary of the concept, indicating the enduring understanding students should retain after class. Summary A combination reaction is a type of reaction which forms a single product from the combination of two or more reagents. Sample Problems Explore sample problems from the JCE QBank and other sources. Sample Problems Works Cited 4 / 5

5 Review the works cited to write the researched parts of this page, such as the discover's biographical information and other areas. Works Cited Birk, James P. "Chemical Reactions." Chemistry: Foundations and Applications. Advameg, Inc., Web. 27 Oct (reaction type descriptions) 5 / 5