1 / 9

Understanding Chemical Reactions: Signs, Conservation of Mass, and Writing Equations

This resource provides a comprehensive introduction to chemical reactions, including key signs such as heat and light evolution, gas and precipitate formation, and color changes. It explains the law of conservation of mass, emphasizing that mass is neither created nor destroyed. Learn how to write balanced chemical equations, identify reactants and products, and use coefficients and physical states. The content covers examples of reactions, such as the combination of hydrogen and oxygen to form water, and the reaction of zinc with hydrochloric acid.

yeva
Télécharger la présentation

Understanding Chemical Reactions: Signs, Conservation of Mass, and Writing Equations

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 Intro to Reactions

  2. A.Signsof a Chemical Reaction • Evolution of heat and light • Formation of a gas • Formation of a precipitate • Color change • http://www.youtube.com/watch?v=fF6FUVxAVzI

  3. B.Lawof Conservation of Mass • mass is neither created nor destroyed in a chemical reaction • total mass stays the same • atoms can only rearrange 4 H 2 O 4 H 2 O 36 g 4 g 32 g

  4. C. Chemical Equations A+B  C+D REACTANTS PRODUCTS

  5. C. Chemical Equations

  6. D. Writing Equations 2H2(g) + O2(g)  2H2O(g) • Identify the substances involved. • Use symbols to show: • How many? - coefficient • Of what? - chemical formula • In what state? - physical state • Remember the diatomic elements.

  7. D. Writing Equations Two atoms of aluminum react with three units of aqueous copper(II) chloride to produce three atoms of copper and two units of aqueous aluminum chloride. • How many? • Of what? • In what state?  3 2 Al (s) + 3 CuCl2 (aq) Cu (s) + 2 AlCl3 (aq)

  8. Describing Coefficients: individual atom = “atom” covalent substance = “molecule” ionic substance = “unit” E. Describing Equations 3CO2 2Mg  4MgO  3 molecules of carbon dioxide 2 atoms of magnesium 4 units of magnesium oxide

  9. E. Describing Equations Zn(s) + 2HCl(aq)  ZnCl2(aq) + H2(g) to produce • How many? • Of what? • In what state? One atom of solid zinc reacts with two molecules of aqueous hydrochloric acid one unit of aqueous zinc chloride and one molecule of hydrogen gas.

More Related