1. Science Starter  What is the charge of the element magneiusm?  What is the charge of the magneiusm ion?  What is the formula and name of bonding magnesium ion to the chlorate ion?

2. Unit 7 Chemical Reactions Basic Chemical Reactions

3. What is a Chemical Reaction?  Chemical reactions are just the rearrangement of atoms.  There are 4 signs of chemical reactions. These include:  Formation of Precipitate  Color Change  Heat/Light  Gas Formation  Reactants react to produce products.  Reactants  Products  DO NOT FLIP THE ARROW! (we don’t read left to right, it doesn’t make sense, so DON’T DO IT! It gives us chemistry teachers headaches.)

4. Other Important Information About Chemical Reactions  Sometimes you will see some unique signs and symbols.  s, l, g, aq are just physical states (solid, liquid, gas, aqueous)  ∆ is the greek letter delta (means change) and is used to describe heat that is given to a reaction.  Sometimes things like a catalyst is used over the arrow to describe something that speeds up a chemical reaction.  It is not a reactant or a product.

5. Other important information  All new compounds still follow ALL of the naming and formula writing rules.  NEVER CARRY A SUBSCRIPT  If you do this, you will make the compound not neutral and that can ruin the following steps in the unit.  Know your diatomic elements (Mr. Br 2 I 2 N 2 Cl 2 H 2 O 2 F 2 ) and know their physical states!  Know basic physical states for items  H 2 O (l) is a liquid most of the time.  CO 2 (g), SO 2 (g), NO 2 (g), CH 4 (g)-common name is methane, NH 3 (g)- common name is ammonia are all gases.  Metals like JUST Ca(s), Na(s), Fe(s), Cu(s) are all solids.

6. 5 Types of Chemical Reactions  Double Replacement  Single Replacement  Known a lot of the times as a redox reaction  (One item loses electrons while another species gains them)  Synthesis (combination)  Decomposition  Combustion

7. Double Replacement Examples  Double replacement reactions involve two ionic compounds that react.  This is where both the cation and anions of each chemical switch.  It is like two people dancing and bump into each other which cause them to switch partners halfway through the song.  Please note that you have to make the compounds neutral if you have to predict the products.  AB + CD  AD + CB  The order of the reactants or the products does not matter AS LONG AS YOU KEEP THEM AS REACTANTS AND PRODUCTS!

8. Single Replacement Examples  Single replacement involves a compound and a single element.  The compound is broken up by the other similar substance  Look at the single species and see if it could be a cation or anion. Then swap it with the ionic compound.  It is like a partner cutting into a couples dance.  Please note that you have to make the compounds neutral if you have to predict the products. Watch for diatomics!  AB + C  AC + B  C is an anion in this example.  AB + C  CB + A  C is an cation in this example.  The single species can be a metal or non-metal! I should get in on that…

9. Synthesis Examples  This is also known as a combination reaction.  Two or more species (whether they are a compounds or elements) form ONE SINGLE PRODUCT.  A+B  AB  Please note that you have to make the compounds neutral if you have to predict the products.  Keep an eye out for diatomics!

10. Decomposition Examples  One compound is broken down (decomposed) into two different pieces.  AB  A + B  Please keep note of diatomics!

11. Combustion Examples  A compound containing carbon AND hydrogen reacts with oxygen gas, O 2  When a compound is “ burned” it means there was a combustion reaction.  Products will ALWAYS BE CO 2 AND H 2 O  C x H y + O 2  CO 2 + H 2 O  You may also have other elements in your reactant compound other than C and H, such as nitrogen and sulfur. These will form new compounds based on what is “leftover” after you’ve created CO 2 and H 2 O.  C 2 H 5 SH + O 2  CO 2 + H 2 O + SO 2

12. Identifying the Reaction  From the following reactions, please classify them as SR, DR, S, D, or C:

13. TRY ME!  NaOH + KNO 3 → NaNO 3 + KOH  What type of reaction am I?  CH 4 + 2 O 2 → CO 2 + 2 H 2 O  What type of reaction am I?  Ca + NaBr → ____________+ _____________  What type of reaction am I?  __________ + __________ → Ca(OH) 2 + MgSO 4  What type of reaction am I?

14. Word Practice  Please write the chemical equation that matches the following scenarios: