1. CHEMISTRY Jacqueline P. Hancock, B.S.,M.Ed
CHEMICAL REACTIONS
CHEMISTRY
Jacqueline P. Hancock, B.S.,M.Ed

4. How many atoms?

8. COUNTING ATOMS WKSHEET

9. CHEMICAL REACTION One or more substances changes
into another substance
Reactants Products
Reactants yields Products
Reactants produces Products
Reactants equals Products

10. CHEMICAL EQUATION Representation of a chemical reaction using formulas
Skeleton equation- equation w/o amounts of reactants and products(starting point)
Physical states(s-solid, g-gas, l-liquid, aq-dissolved in water
Catalysts-speeds up a reaction w/o being consumed(written above the yields sign)
heat added elec. – electrical current

12. Purpose of Balancing Equations?

13. CONSERVATION OF MASS Dalton’s Atomic Theory
Reactants are converted to products by breaking and forming bonds.
Atoms are rearranged
Mass is conserved
Atoms are conserved

14. Parts of the Chemical Equation

15. Never change subscripts!!!
Recall these numbers were part of the original formation of the ionic or covalent bond forming the substance

16. You can only add/change Coefficients to balance equations

17. Counting Atoms in Equations

18. PRACTICE
MgO + H3PO Mg3(PO4)2 + H2O

19. KI K + I2

20. CH4 + O CO2 + H2O

21. Practice Balancing Equations
Practice Balancing Equations 15 minutes(Balancing Act Worksheet)
Balancing Chemical Reactions Worksheet (a-n)
Progress Reports will be given at the “end” of class

22. Turn in Assignments

23. Types of Reactions Combination(Synthesis) Decomposition
Single Displacement
Double Displacement
Combustion

24. Synthesis
Two or more substances combine to form a single new substance
Metal + Nonmetal
metal cation & nonmetal anion
Nonmetal + Nonmetal
More than one product possible
Transition Metal + Nonmetal

25. Examples of Synthesis Reactions (m + nm, nm + nm, or tm + nm)
2Mg(s) + O2(g) MgO(s)
2K(s) + Cl2(g) KCl(s)
S(s) + O2(g) SO2(g) Sulfur dioxide
2S(s)+3O2(g) 2SO3(g) Sulfur trioxide
Fe(s) + S(s) FeS(s) Iron(II) sulfide
2Fe(s) +3S Fe2S3(s) Iron(III) sulfide

26. Decomposition
Single compound breaks down into two or more simpler products
One reactant and two or more products
Requires energy (heat, light, or elec.)

27. Single Displacement Rxns
One element replaces a second element in a compound
Reactivity decreases down the activity series
Reactive metals will replace any metal below it in activity series

29. A + BC AC+ B

33. Double Displacement Rxns
Exchange of cations between two compounds
Generally take place in (aq) solution
One of the products formed
Precipitate
Gas or
water

35. Combustion Rxns
Element or compound reacts with oxygen producing heat and light
Always involves oxygen as the reactant
Often other reactant is hydrocarbon
Production of CO2
Soot(C)
CO (carbon monoxide)

36. which it breathes
IGNITE

37. How is the cook stove a real life example of a fire triangle?

40. Type of Reaction Definition
 Equation
Synthesis
Decomposition
Single Replacement
Double Replacement
Two or more elements or compounds combine to make a more complex substance
A + B → AB
AB → A + B
Compounds break down
into simpler substances
Occurs when one element replaces another one in a compound
AB + C → AC + B
Occurs when different atoms in two different compounds trade places
AB + CD → AC + BD