1. Chapter 8 Section 1
Chemical Equations reactants → products reactant- starting substance in a chemical reaction product- substance formed in a chemical reaction → = yields, gives you, produces, goes to **Law of Conservation of Mass holds true here mass of reactants = mass of products

2. -the states of matter can be indicated after the substance (s)=solid (ℓ)=liquid (g)=gas (aq)=aqueous  = reversible reaction catalyst- substance that speeds up the rate of a reaction without being used up in the reaction **written above the arrow ex- Pt ∆ = heat applied

3. **Remember elements that cannot exist alone H O N Cℓ Br I F skeleton equation- chemical equation that is not balanced ex- Write a skeleton equation for the following reaction: solid iron reacts with oxygen gas to form solid iron (III) oxide Fe(s) + O2(g) → Fe2O3(s)

4. Try these:
1) solid sodium hydrogen carbonate reacts with aqueous hydrogen chloride to produce aqueous sodium chloride, water and gaseous carbon dioxide
NaHCO3(s) + HCℓ(aq) → NaCℓ(aq) + H2O (ℓ) + CO2(g)
solid sulfur burns in oxygen gas to form sulfur dioxide gas
S(s) + O2(g) → SO2(g)

5. 3) solid potassium chlorate forms oxygen gas and solid potassium chloride in the presence of catalyst manganese (II) oxide KCℓO3(s) MnO O2(g) + KCℓ(s)

6. Balancing Equations -each side of the equation (reactants and products) must have the same # of each element -some may already be balanced -must be lowest whole # ratio -balance by putting coefficients in front of compounds

7. Chapter 8 Section 2 **Remember H O N Cℓ Br I F
Types of Chemical Reactions
Combination/Synthesis Reaction
-two or more substances combine to form a single substance
reactants- two elements or two compounds
products- always a compound
ex- 2K + Cℓ2 → 2KCℓ
ex- SO2 + H2O → H2SO3

8. Try these. Don’t forget to balance
Try these!! Don’t forget to balance!! a) aluminum + oxygen → Aℓ + O2 → Aℓ + O2 → Aℓ2O3 b) beryllium + oxygen → Be + O2 → Be + O2 → BeO c) strontium + iodine → Sr + I2 → Sr + I2 → SrI2 d) magnesium + nitrogen → Mg + N2 → Mg + N2 → Mg3N2 4 3 2 2 2 3

9. Decomposition Reaction
-one compound breaks down or decomposes into two simpler compounds
-the reverse of synthesis
ex- 2H2O → 2H2 + O2
Try these!!
a) lead(IV) oxide →
PbO2 →
PbO2 → Pb + O2
hydrogen iodide →
HI →
HI → H2 + I2 2

10. c) hydrogen bromide → HBr → HBr → H2 + Br2 d) sodium chloride → NaCℓ → NaCℓ → Na + Cℓ2

11. Single-Replacement Reactions
-one element replaces a second element in a compound
ex- 2K + CaO → K2O + Ca
-whether one metal will replace another metal is determined by reactivity of the metal
activity series of metals- lists metals in order of decreasing reactivity
**Page 217
-a metal will replace another metal listed below it in the table

12. ex- Mg + Zn(NO3)2 →. is Mg above Zn on the reactivity series
ex- Mg + Zn(NO3)2 → *is Mg above Zn on the reactivity series? Mg + Zn(NO3)2 → Mg(NO3)2 + Zn ex- Mg + Ag2SO4 → Mg + Ag2SO4 → MgSO4 + Ag ex- Mg + LiNO3 → -lithium is above magnesium Mg + LiNO3 → no reaction (NR) 2

13. -Halogens can replace each other in single-replacement reactions
-Reactivity decreases as you go down the halogen group
Try These!!
zinc + hydrogen sulfate →
Zn + H2SO4 →
Zn + H2SO4 → H2 + ZnSO4
chlorine + sodium bromide →
Cℓ2 + NaBr →
Cℓ NaBr → Br NaCℓ 2 2

14. c) zinc + sodium nitrate → Zn + NaNO3 → no reaction d) iron(II) + lead(II) nitrate → Fe + Pb(NO3)2 → Fe + Pb(NO3)2 → Pb + Fe(NO3)2 e) chlorine + sodium iodide → Cℓ2 + NaI → Cℓ2 + NaI → I2 + NaCℓ 2 2

15. Double-Replacement Reactions
-involve an exchange of cations between two reacting compounds
ex- BaCℓ2 + K2CO3 → BaCO KCℓ
ex- FeS + 2HCℓ → H2S + FeCℓ2
Try These!!
sodium hydroxide + iron(III) nitrate →
NaOH + Fe(NO3) 3 →
NaOH + Fe(NO3) 3 → NaNO3 + Fe(OH)3 3 3

16. barium nitrate + hydrogen phosphate → Ba(NO3) 2 + H3PO 4 →
Ba(NO3) H3PO 4 → Ba3(PO4) HNO3
potassium hydroxide+hydrogen phosphate →
KOH + H3PO4 →
KOH + H3PO4 → K3PO H2O
d) hydrogen sulfate + aluminum hydroxide →
H2SO4 + Aℓ(OH)3 →
H2SO Aℓ(OH)3 → Aℓ2(SO4) H2O 3 2 6 3 3 3 2 6

17. -hydrocarbon combined with oxygen to produce carbon dioxide and water
Combustion Reaction
-hydrocarbon combined with oxygen to produce carbon dioxide and water
ex- C6H6 + O2 → CO2 + H2O
-to balance:
*always begin with a 2 in front of hydrocarbon
*when done, if can divide by 2 do so
C6H O2 → CO H2O 15 2 6 12

18. Try These!! C14H26 + O2 → C14H26 + O2 → CO2 + H2O C8H12 + O2 →41 28 22 16 12 2

19. Summary of Reactions
Combination/Synthesis
R + S → RS
Decomposition Reaction
RS → R + S
Single-Replacement Reaction
T + RS → R + TS
Double-Replacement Reaction
RS + TU → RU + TS
Combustion Reaction
CxHy + O2 → CO2 + H2O

20. Precipitation Reactions
soluble- able to dissolve insoluble- not able to dissolve precipitation reaction- a reaction in which soluble ions combine to form an insoluble compound that settles out of solution as a solid *are double-replacement reactions

21. precipitate- insoluble solid formed during a precipitation reaction
precipitate- insoluble solid formed during a precipitation reaction *must look at solubility rules -write (s) after compound formula if insoluble -write (aq) after compound if soluble

22. For each of the following compounds, tell if they are soluble or insoluble.
MgCℓ2
Be(OH)2
Cs2CO3
Na2SO4
KOH
SrCO3
7. ZnSO4
LiI
soluble (aq)
insoluble (s)
soluble (aq)
soluble (aq)
soluble (aq)
insoluble (s)
soluble (aq)
insoluble (s)

23. Ba(NO3) 2(aq) + H3PO4(aq) → Will precipitate form
Ba(NO3) 2(aq) + H3PO4(aq) → Will precipitate form? Ba(NO3) 2(aq)+ H3PO4(aq) → Ba3(PO4) 2 + HNO3 3 2
(s) 6
(aq)

24. KCℓ(aq) + MgSO4(aq) → KCℓ(aq)+ MgSO4(aq) → K2SO4 +MgCℓ2