1. Equations Word equations Skeleton equations Balancing equations

2. Word equations Word equation  represents a chemical reaction using words to explain the reaction Ex. Hydrogen and oxygen combine to form water. A + B  C + D reactants products Combine to form OR yields OR produces

3. Skeleton equation Hydrogen and oxygen combine to form water Becomes: H 2(g) + O 2(g)  H 2 O (l) ** notice that all the species are written as compounds with the states included. (g) is gas (l) is liquid (s) is solid (aq) is aqueous

4. Balancing Equations The goal is to have the SAME amount of similar atoms on both sides of the reaction. We balance an equation because we need to adhere to the First Law of Thermodynamics which states that matter is neither created nor destroyed.

5. Rules 1.The chemical formula cannot be changed. 2.If you have a word equation start by writing a skeleton equation before trying to count atoms. 3.Using a table, count the number of atoms in both the products and reactants. 4.ONLY coefficients can be added IN FRONT of the molecule in order to help with the balancing.

6. examples 1.Sodium and chlorine combine to form sodium chloride. Na (s ) + Cl 2(g)  NaCl (s) Count atoms 1Na: 1Na 2Cl: 1Cl 2Na (s ) + Cl 2(g)  2 NaCl (s) Count atoms again 2Na:2Na 2Cl:2Cl DONE!

7. Try these! 1.__Na + __ O 2  __ Na 2 O 2.__ K + __ Cl 2  __ KCl 3.__ Al + __ Br 2  __ AlBr 3 4.__ Li + __ S  __ LiS 2 5.__ Mg + __ N 2  __ Mg 3 N 2 6.__ Na + __ H 2 0  __ NaOH + __ H 2 7.__ O 3  __ O 2 8.__ Al 2 O 3  __ Al + __ O 2 9.__ P 4 + __ O 2  __ P 4 O 10 10.__ FeS 2 + __ O 2  __ Fe 2 O 3 + __ SO 2

8. Write and balance the following word equations. 1.Iron metal and oxygen gas yield iron (III) oxide. 2.Nitrogen gas and hydrogen gas produce gaseous ammonia. 3.Solid barium chloride and solid magnesium sulphate produce solid barium sulphate and aqueous magnesium chloride.

9. Practice Sheet balancing questions chembalancer

10. 1.__Na + __ O 2  __ Na 2 O 2.__ C + __ O 2  __ CO 2 3.__ Na + __ Cl 2  __ NaCl 4.__ Hg + __ O 2  __ HgO 5.__ Mg + __ HCl  __ MgCl 2 + __ H 2 6.__ Ca + __ N 2  __ Ca 3 N 2 7.__ BiCl 3 + __ H 2 S  __ Bi 2 S 3 + __ HCl 8.__ P 4 + __ I 2  __ PI 3 9.__ H 2 O 2  __ O 2 + __ H 2 O 10.__ Fe + __ O 2  __ Fe 3 O 4 11.__ CaO + __ C  __ CaC 2 + __ CO 2 12.__ AsBr 3 + __ H 2 S  __ As 2 S 3 + __ HBr 13.__ H 2 + __ O 2  __ H 2 O 14.__ Br 2 + __ KI  __I 2 + __KBr 15.__ FeS + __ O 2  __ Fe 2 O 3 + __ SO 2 16.__ N 2 + __ H 2  __ NH 3 17.__ Na(NO 3 ) + __ K  __ K(NO 3 ) + __ Na 18.__ Fe + __ H 2 O  __ Fe 3 O 4 + __ H 2