1.  Representing Chemical Reactions Word and Chemical Equations

2. Scientists can represent chemical reactions in 2 ways:  1. Word Equations  Word equations use chemical names to represent what reacts/what is being used up (your reactants ) and what is being made/produced (your products )  All Reactants  All Products

3. Word Equations Cont’d  Reactant 1 + Reactant 2  Product 1 + Product 2  A very useful skill is converting a description of a chemical reaction into a word equation  Its basically a summary of what is going on

4. Example  When zinc metal is added to a hydrochloric acid solution, hydrogen gas and a colourless solution called zinc chloride result.  W.E. (word equation)  Zinc + hydrochloric acid  hydrogen gas + zinc chloride  ** Notice that hydrogen is the only molecule that has been given a state in the word form….why????**

5. Symbols used in Chemical Equations  “  ” separates the reactants from the products and is read as “reacts to form” or “yields”  “+” is used to separate all the reactants from one another and all of the products from one another and is read as “and”  (s) – stands for a solid  (l) – stands for liquid  (g) – stands for gas  (aq) – stands for aqueous solution (dissolved in water)

6. Another Word Equation Example  Magnesium ribbon is added to oxygen in the air to form a compound known as magnesium oxide  W.E.

7. 2. Chemical Equations  Chemical Equations use chemical formulas to represent the reactants and the products being used  There are 2 types of chemical equations  1. Skeleton Equations (OOOoooOoOoOoOoo)  An equation that has NOT been balanced  2. Balanced Chemical Equations  An equation where the number of atoms on the reactants side equals the number of atoms on the products side

8. Example  W.E.  Zinc +hydrochloric acid  hydrogen gas + zinc chloride  Transfer a word equation into a chemical equation  Change the chemical words into chemical symbols and add their states (s,l,g,aq), keep the math symbols as is!  Zn (s) + HCl (aq)  H 2(g) + ZnCl 2(aq)

9. Example 2  Magnesium + oxygen gas  magnesium oxide  C.E. _____ + _______  __________________

10. Complete the Handout