Types of Chemical Reactions s1

Chapter 11 now beginning

There are MANY types of Chemical reactions; we will start with a few

Reactants à Products

(Read as reactants react to form Products)

Some reactions take in energy and are “endothermic”

Some reactions give off energy and are “exothermic”

Remember energy is in j (joules) or Kilojoules (kJ)

KNOW THE SEVEN DIATOMIC ELEMENTS!!!!!!!

(I2, Br2, Cl2, F2, O2, N2, H2)

( I Bring Clay For Our New House; Mr/Ms HOFBrINCl’s house)

Types of Chemical Reactions

Now that you know something about elements and compounds, lets see how they can react to for different stuff! Just like with Lego’s (the snap together building blocks) you can put them together, take them apart or swap them around.

1. A DECOMPOSITION reaction starts with one reactant and ends up with two or more products. Which of the following reactions are decomposition reactions? Circle the letters.

a) NaCl à Na + Cl2

b) Na + Cl2 à NaCl

c) H2O à H2 + O2

d) NaOH + HCl à HOH + NaCl

e) H2 + O2 à H2O

2. A SYNTHESIS reaction starts with two reactants and ends up with one product. Which of the following reactions are synthesis reactions? Circle the letters.

a) NaCl à Na + Cl2

b) Na + Cl2 à NaCl

c) H2O à H2 + O2

d) NaOH + HCl à HOH + NaCl

e) K +Cl2 à KCl

3. A SINGLE REPLACEMENT reaction starts with two reactants and ends up with two products. The uncombined element takes the place of the combined element in the compound. Which of the following reactions are single replacement reactions? Circle the letters.

a) NaCl à Na + Cl2

b) NaOH + HCl à HOH + NaCl

c) K + AgCl2 à Ag + KCl

d) Na + HCl à H2 + NaCl

e) H2O à H2 + O2

4. A DOUBLE REPLACEMENT reaction starts with two reactants and ends up with two products. In this case both reactants are compounds and both products are compounds. Which of the following reactions are double replacement reactions? Circle the letters

a) NaOH + HCl à HOH + NaCl

b) Na + HCl à H2 + NaCl

c) K + AgCl2 à Ag + KCl

d) KOH + HNO3 à KNO3 + HOH

e) Ca + S à CaS

5. A COMBUSTION reaction is when the reactants are oxygen and a hydro carbon and the products are water and carbon dioxide.

6. A NEUTRALIZATION reaction is a special type of double replacement reaction that will be covered in detail later on.

By now something should be bothering you about many of the Chemical Equations listed above. Many of them ARE NOT BALANCED. Please follow the teacher examples of how to balance equations.
Identifying and Balancing Chemical Equations

Name: ______period: ____

Balance these equations (even if the value is one put it in the blank) and identify the type of reaction. (Synthesis, Decomposition, Single Replacement, Double Replacement or Combustion) Type of reaction

1. __HgO __Hg + __O2 ______

2. __ NaCl + __ AgNO3 __NaNO3 + __AgCl ______

3. __ Cl2 + __ Ca __ CaCl2 ______

4. __ C2H6 + __ O2 __CO2 + __H2O ______

5. __ H2O + __ Fe __ Fe2O3 + __ H2 ______

6. __ Al2S3 + __Ca(OH)2 __ Al(OH)3 + __ CaS ______

7. __ S8 + __ Fe __ FeS ______

__ N2 + __ H2 __ NH3 ______

9. __ KClO3 __ KCl + __ O2 ______

10. __ Al2(SO4)3 + __Ca(OH)2 __ Al(OH)3 + __ CaSO4 ______

Glencoe Chapter 9 book problems (start on p288): 7-12

(Prentice Hall) Chapter 11 book problems: 1, 2, 3, 4, 11, 12, 14, 15, 18, 24, 28, 41, 49, 51, 54

Types of Chemical Reactions with answers

1. A DECOMPOSITION reaction starts with one reactant and ends up with two or more products. Which of the following reactions are decomposition reactions? Circle the letters.

a) NaCl à Na + Cl2

b) Na + Cl2 à NaCl

c) H2O à H2 + O2

d) NaOH + HCl à HOH + NaCl

e) H2 + O2 à H2O

2. A SYNTHESIS reaction starts with two reactants and ends up with one product. Which of the following reactions are synthesis reactions? Circle the letters.

a) NaCl à Na + Cl2

b) Na + Cl2 à NaCl

c) H2O à H2 + O2

d) NaOH + HCl à HOH + NaCl

e) K +Cl2 à KCl

a) NaCl à Na + Cl2

b) NaOH + HCl à HOH + NaCl

c) K + AgCl2 à Ag + KCl

d) Na + HCl à H2 + NaCl

e) H2O à H2 + O2

a) NaOH + HCl à HOH + NaCl

b) Na + HCl à H2 + NaCl

c) K + AgCl2 à Ag + KCl

d) KOH + HNO3 à KNO3 + HOH

e) Ca + S à CaS

5. A COMBUSTION reaction is when the reactants are oxygen and a hydro carbon and the products are water and carbon dioxide.

6. A NEUTRALIZATION reaction is a special type of double replacement reaction that will be covered in detail later on.

Name: ______ANSWERS______period: ____

1. _2_HgO + _2_Hg + _1_O2 __Decomposition_

2. _1_ NaCl + _1_ AgNO3 _1_NaNO3 + _1_AgCl _Double Replace_

3. _1_ Cl2 + _1_ Ca _1_ CaCl2 ___Synthesis___

4. _2_ C2H6 + _7_ O2 _4_CO2 + _6_H2O __combustion___

5. _3_ H2O + _2_ Fe _1_ Fe2O3 + _3_ H2 _single replacement_

6. 1 Al2(SO4)3 + 3 Ca(OH)2 2 Al(OH)3 + 3 CaSO4 _Double Replace_

7. _1_ S8 + _8_ Fe _8_ FeS ___ Synthesis __

_1_ N2 + _3_ H2 _2_ NH3 __ Synthesis __

9. _2_ KClO3 _2_ KCl + _3_ O2 __Decomposition_

10. 1 Al2(SO4)3 + 3 Ca(OH)2 2 Al(OH)3 + 3 CaSO4 __Double Replace_

Review warm-up for the limiting reagents part of Stoichiometery

Review: What type of reactions are these?

1) NaOH + KNO3--> NaNO3+ KOH

2) CH4+ 2 O2--> CO2+ 2 H2O

3) 2 Fe + 6 NaBr --> 2 FeBr3+ 6 Na

4) CaSO4+ Mg(OH)2--> Ca(OH)2+ MgSO4

5) NH4OH + HBr --> H2O + NH4Br

6) Pb + O2--> PbO2

7) Na2CO3--> Na2O + CO2

- Skeletal equation (bare bones)

- Balanced equation (minimum necessary to do stoichiometry calculations)

- Balanced equation with phase information

o (solid (s), liquid (l), Gas(g), aqueous solution (aq))

- (Equations where everything is written as ions, elements or molecules help you understand how to balance the compounds and then the equation)

- Net ionic equations: then you strip away any ion that stay in solution from the
Chapter 11 book problems: 1, 2, 3, 4, 11, 12, 14, 15, 18, 24, 28, 41, 49, 51, 54

Book problem answers:

1) Solid sodium metal and liquid water react to form a solution of sodium hydroxide and bubbles of hydrogen gas.

2) S(s) + O2(g) à SO2 (g) but you might not know this

3) a) 2 AgNO3 + H2S à Ag2S + 2 HNO3

b) 3 Zn(OH)2 + 2 H3PO4 à Zn3(PO4)2 + 6 H2O

4) a) H2 + S à H2S

b) FeCl3 + Ca(OH)2 à Fe(OH)3 + CaCl2

11) a) Fe(s) + Cl2(g) à FeCl3(s)

b) Al2(CO3)3(s) à Al2O3(s) + CO2(g)

12) a) 2 SO2 + O2 à 2 SO3

b) Fe2O3 + 3 H2 à 2 Fe + 3 H2O

c) 4 P + 5 O2 à P4O10

d) 2 Al + N2 à 2 AlN

14) 3 Mg(s) + N2(g) à Mg3N2 ; remember diatomic elements (I Br Cl F O N H)

15) Complete and balance this decomposition reaction:

2 HI à H2 + I2

18) Write the products of these double-replacement reactions. Then Balance each equation.

a) 3 NaOH(aq) + Fe(NO3)3(aq) à Fe(OH)3(s) + 3 NaNO3

b) 3 Ba(NO3)2(aq) + 2 H3PO4(aq) à Ba3(PO4)2(s) + 6 HNO3(aq)

24) Classify and balance each:

a) 2 C3H6 + 9 O2 à 6 CO2 + 6 H20 combustion

b) 2 Al(OH)3 à Al2O3 + 3 H2O decomposition

c) Li + O2 à Li2O synthesis

d) Zn + 2 AgNO3 à 2 Ag + Zn(NO3)2 single replacement

28) Write the balanced net ionic equation for this reaction. (as written)

Ca2+(aq) + OH-(aq) + H+(aq) + PO4-3(aq) à

Ca2+ + PO43-(aq) + H2O(l)

You just don’t write the stuff that is on both sides: so…

Ca2+(aq) + OH-(aq) + H+(aq) + PO4-3(aq) à

Ca2+ + PO43-(aq) + H2O(l)

Or simplified it is: OH-(aq) + H+(aq) à H2O(l)

41) Balance each :

a) a bb team: C + 2 F + 2 G à CF2G2

b) a tricycle: F + 3 W + S + 2 P à FW3SP2

49) Write a balanced equation for each of the following double replacement reactions

a) H2C2O4(aq) + KOH(aq) à K2C2O4 + 2 HOH

b) CdBr2(aq) + Na2S(aq) à CdS(s) + 2 NaBr(aq)

51) Write a balanced equation for the complete combustion of each compound

a) C4H8 + 6 O2 à 4 CO2 +4 H2O

b) C3H6O + 4 O2 à 3 CO2 + 3 H2O ; (the reactant also has oxygen)

54) Write a net ionic equation for each of the following reactions.

a) 2 HCl(aq) + Ca(OH)2(aq) à CaCl2 + 2 HOH

as ions it is written as:

2 H+ + 2Cl- + Ca2+ + 2(OH)- à Ca2+ + 2Cl- + 2H2O ; water’s a molecule not an ionic compound

Cross out the ions that are on both sides gives us:

2 H+ + 2Cl- + Ca2+ + 2(OH)- à Ca2+ + 2Cl- + 2H2O

Or 2 H+ + 2(OH)- à 2H2O ( the net ionic equation)

b) AgNO3(aq) + AlCl3(aq) à silver chloride is a precipitate

so… 3 AgNO3(aq) + AlCl3(aq) à 3 AgCl(s) + 1 Al(NO3)3(aq)

as ions it is:

3 Ag+ + 3 (NO3)-(aq) + Al3+ + 3Cl-(aq) à 3 AgCl(s) + 1 Al3+ + 3(NO3)-(aq)

Cross out the same ones to get net ionic:

3 Ag+ + 3 (NO3)-(aq) + Al3+ + 3Cl-(aq) à 3 AgCl(s) + 1 Al3+ + 3(NO3)-(aq)

Or simply: 3 Ag+ + 3Cl-(aq) à 3 AgCl(s) (the net ionic equation)

The activity series of metals

Chemical Equations

Name: ______period: ____

Name / Symbol
Lithium / Li
Potassium / K
Calcium / Ca
Sodium / Na
Magnesium / Mg
Aluminum / Al
Zinc / Zn
Iron / Fe
Lead / Pb
(hydrogen) / H
Copper / Cu
Mercury / Hg
Silver / Ag

Look at the activity series for metals on page 333 of you text; (or at the following table)

Note: decreasing activity top to bottom

· Metals from Li to Na will replace H from acids and water; From Mg to Pb they will replace H from acids only

Predict if any reaction will take place. Balance the equations or any reaction that will occur

11. Mg(s) + FeSO4 (aq)

12. Mg(s) + NaCl (aq)

13. Fe(s) + Pb(NO3)2 (aq)

14. Cu(s) + Al2(SO4)3 (aq)

15. Ag(s) + ZnS (aq)

16. Zn(s) + H2O (l)

17. Ag(s) + H2SO4 (aq)

18. Fe(s) + HCl (aq)

19. Na(s) + H2O (l)

20. Pb(s) + H2O (l)

21. Li(s) + Mgl2 (aq)

22. Al(s) + HCl (aq)

· The seven diatomic elements

· H2, N2, O2, F2, Cl2, Br2, I2

· When in their natural state (gases since most have very low boiling points) these elements “pair up” into molecules (non-metal to non-metal). They seem to do this to have a complete valence shell. You must have these memorized in order to properly write balanced chemical equations. Here are some tricks I have learned.

· An oldie but a goodie

· I Bring Clay For Our New House

· ( 4 paving 8 sidewalks; P4 S8 )

· One teacher said all the elements got together to honor to honor a great chemistry Ms. (or Mr.) HOFBrINCl (spell it just like it sounds)

· One particularly energetic cheerleader noticed that it was H (hockey puck) and a hockey stick (3 across and 4 down N, O, F, Cl, Br, I).

· However you wish to memorize them JUST DO IT !!!