Experiment 5: Types of reactions

Question 1

Combustion

Answer 1

Substances combine with oxygen and produce CO2 and water.

CH4+ 2O2 –> CO2 +2H2O

Question 2

Oxidation

Answer 2

Oxidation state changes, lose electrons.

Sn2+ –> Sn3+ + e^-

Question 3

Single Displacement

Answer 3

AB + C —> AC + B

Question 4

Double Displacement

Answer 4

AB + CD —> AC + BD

Question 5

Combination

Answer 5

A + B –> AB

Question 6

Gas Evolution

Answer 6

Gas bubbles and effervescence is apparent, often CO2.

Question 7

Acid-Base

Answer 7

Acid base,

HNO3 + NH3 –> NH4NO3

Question 8

Reduction

Answer 8

Gain electrons

FE3+ + e^- –> Fe2+

Question 9

Precipitation

Answer 9

leads to formation of insoluble product.

Na2SO4 + BA(NO3)2 –> Ba(SO4) (s) + 2NaNO3

Question 10

Na2SO4 + Ba(NO3)2 –> ____

Answer 10

Precipitation;

Ba(SO4) (s) + 2NaNO3

Question 11

Sn^2+ –> Sn^3+ + e^-

Answer 11

Oxidation

Question 12

Fe^3 + e^- –>Fe^2+

Answer 12

Reduction

Question 13

A+B–> AB

Answer 13

Combination

Question 14

CH4 + 2O2 –> CO2 + 2H2O

Answer 14

Combustion

Question 15

AB + CD –> AC+ BD

Answer 15

double displacement

Question 16

HNO3+NH3 –> _____

Answer 16

Acid-Base

Question 17

AB + C –> AC + B

Answer 17

Single displacement

Question 18

CaCO3 –> CaO + CO2

Answer 18

Gas evolution

Question 19

Visual reaction cues? (3)

Answer 19

Precipitation, color change, gas evolution

Question 20

Non-visual reaction cues? (3)

Answer 20

pH, temperature, conductivity

Question 21

Conductivity is…

Answer 21

1/R, 1/Ohms, Mho

Question 22

Ions carry ____.

Answer 22

Electricity

Question 23

High ion concentration = ______ conductivity

Answer 23

High

Question 24

Smaller ions = ________ conductivity.

Answer 24

Higher (if both have same charge)

Question 25

Higher charge = ______ higher conductivity.

Answer 25

higher (usually)

Question 26

+2 is twice as conductive as +1. True/false?

Answer 26

False

Question 27

Higher charge results in….

Answer 27

Solvation, surrounding of charge by water ions whose neg O is attracted to cations and H is attracted to Anions. This is why +2 =/ (+1)*2

Question 28

Endothermic reactions ______ heat.

Answer 28

Absorb

Question 29

Exothermic reactions ______ heat

Answer 29

release

Question 30

HCL +H2O --> H3O^+ +Cl^-
H3O^+ + Cl^- + NaOH --> Na + Cl + H2O. 
Type?
Conductivity?
Temperature?

Answer 30

Type: Dissolution, acid-base

Conductivity: 1) Linear rise with HCL, 2)same linear fall with NaOH, 3)equivalence point at bottom of v right here(mole HCL = mole NaOH), 4) Adding excess NaOH rises

Temp: Not substantial

Question 31

H2O+NH3–>NH4+OH

NH4+OH+Cu(NO3)2 –> Cu(OH)2 (s) + NH4+NO3

Answer 31

Dissolution, acid-base, precipitate.

Conductivity: Rises with NH3, rounds off and decreases with Cu(NO3)2.

Temp: Not substantial.

Question 32

H2CO3 –> H2O + CO2 (g)

Answer 32

Gas evolution

Conductivity: Rises, rounds off, falls slightly

Temp: Not substantial

Question 33

Na+Cl+H2O+KNO3–> Na+Cl+H2O+K+NO3

Answer 33

Type: simple dissolution (no reaction)

Conductivity: Add Nacl=..25x, add KNO3=2x
(Exception here that larger(K +NO3) ions are better conductors than Na and Cl

Temp: Not substantial

Question 34

NA2SO4+H2O–>2NA + SO4 + H2O

NA2SO4+Ba(NO3)2—> 2NA + 2NO3 + BaSO4(s)

Answer 34

Simple dissolution, precipitation

Cond: Add Na2SO4-y=x, Add Ba(NO3)2=-.5x

Temp: Not substantial

Question 35

2FeCL3 + 3Sn —> 2Fe+ 3SnCl2

Answer 35

Type: (+3-1)+0–>0+(+2-1)
Reduction in oxidation number=redox. Sn oxidized, Fe reduced. Natural atoms oxidation number =0

Cond: Don’t care
Temp: Don’t care

Question 36

Mg(s) +HCL–> MgCl2 + H2 (g)

Answer 36

Type: redox, acid-base, gas evolution.

conductivity: .5x, -.25x

Temp: Linear rise, not from 0.