Week 5 (Ion Exchange Reactions)

Question 1

Ion exchange reaction

Answer 1

-chemical reaction between two substances that involves exchange of one of more ionic components (swapping ions between solution and solid phase)
-ex. NaOH(aq) + AgNO3(aq) -> AgOH(s) + NaNO3(aq)
-ex. Na2CO3(s) + 2HCl(aq) -> 2NaCl(aq) + H2O + CO2(aq)

Question 2

Ion Exchange steps

Answer 2

-mix 2 solutions of soluble ionic compounds (KI(aq) + Pb(NO3)2(aq))
-any positive ion can associate with any negative ion (K+, I-, Pb(2+), NO3(-))
-find products by “swapping partners” (KNO3 -> soluble -> K+ + NO3-)(PbI2 -> insoluble -> PbI2)
-Net Ionic eqaution: 2I-(aq) + Pb(2+)(aq) -> PbI2(s)

Question 3

Spectator ions

Answer 3

ions that are present in a chemical reaction but do not participate in it

Question 4

What makes ion-exchange reaction occur?

Answer 4

for ion exchange reaction AB(aq)+CD(aq) -> AD + CB, AD and CB must be one of these to say the reaction occurred:
-an insoluble compound
-a weak electrolyte
-a compound that dissociates to form a gas

Question 5

How to write net ionic equations

Answer 5

-Molecular equation: AgNo3(aq) + NaOH(aq) -> NaNO3(aq) + AgOH(s)
-Ionic Equation: Ag + No3 + Na + OH -> Na + NO3 + AgOH (cancel ions that appear on both sides)
Net Ionic Equation:
Ag+ + OH- -> AgOH(s)
(net ionic equations are only for reactions that occur in aqueous solution)

Question 6

Flame Test

Answer 6

electrons in atoms that are out into flame have ability to take energy from flame and get into excited state. When electrons return back to ground state, they give off energy (E= hc/wavelength)

Question 7

Balanced chemical equation

Answer 7

upholds the conservation of matter so that all atoms on one side of the reaction are accounted for on the other side. Atoms cannot be created nor destroyed

Question 8

Synthesis reaction

Answer 8

combination of two or more elements/compounds into a single new compound
ex. C (s) + O (g) -> CO2 (g)

Question 9

Decomposition reaction

Answer 9

the separation of a single compound into two or more new elements/compounds (reverse of synthesis)
ex. 2H2O2 (l) -> 2H2O (l) + O2 (g)

Question 10

Single Displacement (Replacement) Reaction

Answer 10

an element reacts with a compound to form a new compound and a different element
ex. Zn (s) + HCl (aq) -> H2 (g) + ZnCl2 (aq)

Question 11

Combustion Reaction

Answer 11

the burning of an element or compound in air in which the element/compound reacts with the oxygen in the air. Combustion reactions release heat and are how fuels provide energy.
ex. S (s) + O2 (g) -> SO2 (g)

Question 12

Double Displacement (Precipitation) Reaction

Answer 12

-the ions between two reacting compounds simply rearrange, does not involve changes in oxidation state
ex. BCl2 (aq) + Na2SO4 (aq) -> BaSO4 (s) + 2NaCl (aq)

Question 13

Precipitation reaction

Answer 13

two soluble ionic compounds mixed in solution exchange ions such that an insoluble ionic compound forms and precipitates out of solution
ex. BCl2 (aq) + Na2SO4 (aq) -> BaSO4 (s) + 2NaCl (aq)
BaSO4 is the precipitate

Question 14

precipitate

Answer 14

the solid formed from the sedimentation of a solid material from a liquid solution