1 / 12

Science 9

Science 9. Aim: To understand what Chemical Reactions are. Agenda. Science Sizzler Chemical Reaction Notes Bill Nye Video: Chemical Reactions Next Weeks class Unit Test Tues 29. Chemical Reactions. Takes place when two or more substances combine to form new substances

nika
Télécharger la présentation

Science 9

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. Science 9 Aim: To understand what Chemical Reactions are

  2. Agenda • Science Sizzler • Chemical Reaction Notes • Bill Nye Video: Chemical Reactions • Next Weeks class • Unit Test Tues 29

  3. Chemical Reactions • Takes place when two or more substances combine to form new substances • A chemical change in a substance results from a chemical change

  4. The launching of a space shuttle • 1,500,000 L of liquid Hydrogen and 545, 000L of liquid oxygen combine to form water. • This reaction produces enough energy to push a shuttle into orbit.

  5. Air Bags in a car • Contain explosive chemical sodium azide (NaN3(s)). • In an accident, the sodium azide reacts to produce large volumes of nitrogen gas and sodium • Sodium then reacts with another compound in the bag to make a less dangerous compound. • 50 grams of sodium azide can produce 50 L of nitrogen gas in milliseconds.

  6. Materials at the start of a reaction are called the Reactants • Materials at the end of a reaction are called the Products. • Ex. Wood + Oxygen Carbon dioxide + water + energy released + = separates reactants and products from each other.  = direction reaction goes (and means produces)

  7. Review Chemical reactions create new substances. Evidence of a reaction may include: • Colour change • Formation of an odour • Formation of solid or gas • Release or absorption of heat. There are exceptions, bubbling may just mean something is boiling

  8. Reactions that release or absorb heat • Exothermic reactions: Chemical reactions in which heat energy is released as a product. • Endothermic reactions: Chemical reactions in which heat energy is absorbed.

  9. Chemical Changes involving oxygen • Combustion • Oxygen reacts with a substance to form new substances and give of energy. • Fire is a common example. • Wood burns to give off heat and light, producing carbon dioxide and water • Could be considered first chemical reaction used by humans.

  10. 2. Corrosion • The slow chemical change that occurs when oxygen in the air reacts with a metal. • A common example is rusting. (oxygen reacts with iron to produce iron oxide) 3. Cellular respiration • Occurs in your body cells. • Sugars react with oxygen to produce energy, water, and carbon dioxide

  11. Comparing Ionic and Molecular Compounds Pg 153 – Examine the tables, and write your observations about molecular and ionic compounds.

  12. Practice Pg. 153 – 1,2, 4-6 Homework to be corrected in class P. 154 1-8, 10, 13

More Related