1 / 16

Chemical Reactions

Chemical Reactions. In chemistry, a reaction occurs when two or more substances interact and something happens. KEY POINTS. A chemical change must occur as it is the result of a chemical reaction. A reaction could include ions , molecules , or pure atoms (elements) . .

vanig
Download Presentation

Chemical Reactions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chemical Reactions In chemistry, a reaction occurs when two or more substances interact and something happens.

  2. KEY POINTS • A chemical change must occur as it is the result of a chemical reaction. • A reaction could include ions, molecules, or pure atoms (elements).

  3. Energy of Chemical Reactions • Endothermic • Exothermic

  4. Endothermic • Energy – absorbed • Required for reaction • Absorbed energy - often heat or electrical energy.

  5. Exothermic • Energy - released • Released energy - originally stored in bonds of reactants • Often heat given off causes product(s) to feel hot. • Reactions involving combustion or burning are exothermic chemical reaction.

  6. REACTION TYPES • SYNTHESIS (Combination) • DECOMPOSITION • SINGLE REPLACEMENT (Displacement) • DOUBLE REPLACEMENT (Double Displacement) • COMBUSTION

  7. Synthesis • Two or more reactants yielding one product is a way to identify a synthesis reaction. • Generic Example: A + B AB H2 + O H2O

  8. Synthesis Example • Simple hydrogen gas combined with simple oxygen gas can produce a more complex substance --- water! S + O2 SO2 reactant + reactant -------> product

  9. Decomposition • A more complex substance (reactant) breaks down into its more simple parts (products). AB A + B • Synthesis and decomposition reactions are opposites. • catalyst – a substance that causes or accelerates a chemical reaction without itself being affected.

  10. Decomposition Example • Water can be broken down into hydrogen gas and oxygen gas. 2H2O 2H2 + O2reactant -------> product + product

  11. Single Replacement • In a single replacement reaction a single uncombined element replaces another in a compound. Two reactants yield two products. A + BC AC + B Mg + 2AgNO3 Mg(NO3)2 + 2Ag

  12. Single Replacement Example • When zinc combines with hydrochloric acid, the zinc replaces hydrogen. Zn + 2HCl ZnCl2 + H2reactant + reactant ------> product + product Demonstration Time!

  13. Double Replacement • In a double replacement reaction parts of two compounds switch places to form two new compounds. Two reactants yield two products. AB + CD AD + CB precipitate - to separate (a substance) in solid form from a solution, as by means of a chemical reaction.

  14. Double Replacement Example • When silver nitrate combines with sodium chloride, two new compounds are formed --silver chloride and sodium nitrate -- because the sodium and silver switched places. AgNO3 + NaClAgCl + NaNO3

  15. Combustion • Combustion reactions always involve molecular oxygen O2. • Anytime anything burns (in the usual sense), it is a combustion reaction. • Combustion reactions are almost always exothermic (i.e., they give off heat).

  16. Works Cited Howcast. " YouTube - Balancing Chemical Equations - H2O ." YouTube - Broadcast Yourself. . N.p., n.d. Web. 5 Mar. 2011. <http://www.youtube.com/watch?v=jdUQzVMB4Hw&feature=player_embedded>. "Types of Chemical Reactions." Utah State Office of Education - USOE - Welcome. N.p., n.d. Web. 5 Mar. 2011. <http://schools.utah.gov/curr/science/sciber00/8th/matter/sciber/chemtype.htm>. brightstorm2. " YouTube - Decomposition Reaction ." YouTube - Broadcast Yourself. . N.p., n.d. Web. 5 Mar. 2011. <http://www.youtube.com/watch?v=yuStJotow2I>. "chemical reactions:combustion." Indiana University Northwest. N.p., n.d. Web. 5 Mar. 2011. <http://www.iun.edu/~cpanhd/C101webnotes/chemical%20reactions/combustion.html>. ochem9. " YouTube - Five Major Chemical Reactions ." YouTube - Broadcast Yourself. . N.p., n.d. Web. 5 Mar. 2011. <http://www.youtube.com/watch?v=tE4668aarck>. tszheichoi. " YouTube - Hygrogen and oxygen from water ." YouTube - Broadcast Yourself. . N.p., n.d. Web. 5 Mar. 2011. <http://www.youtube.com/watch?v=OTEX38bQ-2w&feature=related>. MLA formatting by BibMe.org.

More Related