Unit 4 - Chemical Reactions

Question 1

Physical Processes

Answer 1

Involve changes in intermolecular interactions

Properties change but composition remains the same

Question 2

Physical Processes examples

Answer 2

Phase changes

Formation/separation of mixtures

Question 3

Chemical Processes

Answer 3

Involve the breaking and/or formation of chemical bonds

Question 4

Gray Area b/t physical & chemical processes

Answer 4

Dissolving a salt in water involves breaking ionic bonds and creating ion-dipole interactions

Question 5

Phase change

Answer 5

Changes in intermolecular interactions result in changes in properties but the composition remains the same

Question 6

Phase change examples

Answer 6

NO(s) -> NO(l)

Question 7

Making a solution

Answer 7

Changes in intermolecular interactions result in changes in properties but the composition remains the same

Question 8

Making a solution examples

Answer 8

NH3(l) -> NH3(aq)

Question 9

Chemical Processes

Answer 9

Involve the breaking and/or formation of chemical bonds

Substances are transformed into new substances that may have different properties

Question 10

Chemical processes may be indicated by…

Answer 10

Temperature changes
Production of light
Formation of a gas
Formation of a precipitate
Changes in color

Question 11

Chemical process b/t Sodium & Chlorine may be represented by what equation?

Answer 11

2Na(s) + Cl2(g) -> 2NaCl(s)

Question 12

What is the gray area b/t chemical & physical processes?

Answer 12

Dissolving a salt in water involves breaking ionic bonds and creating ion-dipole interactions

Question 13

Gray area example of dissolving of table salt

Answer 13

NaCl(s) -> Na+(aq) + Cl-(aq)

Question 14

In chemical reactions, the mass and atoms are

Answer 14

Conserved

Mass of reactants = Mass of products

Question 15

Procedure for Balancing Chemical Equations

Answer 15

1- Write chemical formulas for all reactants & products
2- Balance elements that do not exist independently first by adding coefficients
3- Balance elements that exist independently last
4- Check to make sure that both sides are balanced

Question 16

Net Ionic Equation

Answer 16

Only shows the reaction that actually took place

Question 17

Complete Ionic Equation

Answer 17

Shows all of the ions present & precipitate

Question 18

Molecular Equation

Answer 18

Shows the solutions that were mixed & precipitate

Question 19

Ba2+(aq) + SO42-(aq) -> BaSO4(s) is considered a

Answer 19

net ionic equation

Question 20

Ba(NO3)2(aq) + Na2SO4(aq) -> 2NaNO3(aq) + BaSO4(s) is considered a

Answer 20

molecular equation

Question 21

Ba2+ + 2NO3- + 2Na+ +SO42- -> 2Na+ + 2NO3- + BaSO4(s) is considered a

Answer 21

complete ionic equation

Question 22

Limiting reactant

Answer 22

Reactant that is used up limits how far the reactio will proceed

Question 23

Excess Reactant

Answer 23

Reactant that is leftover when the reaction is complete

Question 24

Precipitation Reactions

Answer 24

Attractive forces between oppositely charged ions is greater than the forces of attraction between water molecules and ions

Question 25

All salts containing which ions are soluble in water?

Answer 25

Na+
K+
NH4+
NO3-

Question 26

Oxidation Reduction Reactions

Answer 26

Election transfer reactions

Question 27

When a substance is oxidized, it

Answer 27

Loses electrons

Question 28

When a substance is reduced, it

Answer 28

Gains electrons

Question 29

LEO the lion says GER

Answer 29

loses electrons - oxidized

gains electrons - reduced

Question 30

Single Replacement REDOX rxn b/t iron and copper(II) sulfate

Answer 30

Fe(s) + Cu2+(aq) -> Fe2+(aq) + Cu(s)

Question 31

How can you tell what gets oxidized and what get reduced?

Answer 31

Answer is in the oxidation numbers

Question 32

For an atom in its elemental form, its oxidation number is

Answer 32

zero

Question 33

OD of Mg, H2, O3

Answer 33

ZERO

Question 34

For a monatomic ion, its OD is equal to its

Answer 34

Charge

Question 35

OD of Mg2+

Answer 35

+2

Question 36

OD of Cl-

Answer 36

-1

Question 37

OD for oxygen in a molecular compound is

Answer 37

-2