CEM 142 Exam 3 MSU EXAM QUESTIONS WITH
COMPLETE SOLUTIONS
What |do |you |know |about |reactions? |(make |a |list) |- |CORRECT |ANSWER✔✔--Atoms |are |
conserved. |They |are |only |re-arranged. |
-Properties |of |products |are |emergent |(not |a |mixture |of |the |reactants |properties). |
-Reactions |can |be |classified |by |the |type |of |reaction |(how |it |occurs). |
-Reactions |are |always |accompanied |by |an |energy |change |(can |be |exo |and |endo) |that |results |
from |changed |in |interactions |(bonds |and |IMFs) |in |the |reactants |and |products. |
-Reactions |are |always |accompanied |by |an |entropy |change.
What |are |the |two |main |typed |of |reactions? |- |CORRECT |ANSWER✔✔--Acid-base |
-Redox |
*Always |accompanied |by |a |changed |in |entropy.
Can |you |predict |the |properties |of |products |if |you |know |the |properties |of |the |reactants? |
A. |Yes
B. |No |
C. |It |depends |
D. |I |dont |know |- |CORRECT |ANSWER✔✔--B |
*Properties |include |smell, |melting |point, |boiling |point, |and |color.
For |the |reaction: |A+B-->C
If |A |is |yellow |and |B |is |blue, |what |color |is |C? |
A. |Yellow |
B. |Blue |
,C. |Green
D. |I |dont |know |- |CORRECT |ANSWER✔✔--D
*React |NOT |mix. |C |= |completely |new |product.
What |thermodynamic |function |tells |you |about |how |far |a |reaction |will |"go"? |
A. |Delta |H |
B. |Delta |S |(system) |
C. |Delta |G |
D. |None |of |these |- |CORRECT |ANSWER✔✔--C
*If |(+) |will |NOT |happen. |
*If |(-) |WILL |happen.
What |thermodynamic |function |tells |you |about |how |fast |a |reaction |will |"go"? |
A. |Delta |H |
B. |Delta |S |(system) |
C. |Delta |G |
D. |None |of |these |- |CORRECT |ANSWER✔✔--D |
*Delta |H |= |energy |change |/ |only |heat. |
*Delta |S |= |Number |of |possible |arrangements |in |system. |
*Delta |G |= |How |far |the |reaction |will |go.
Reactions |can |"go" |both |____________ |and |_____________! |The |sign |of |__________ |will |tell |
you |whether |a |reaction |will |go |forwards |or |backwards. |- |CORRECT |ANSWER✔✔--Forwards |and
|Backwards. |
-Delta |G.
How |fast |a |reaction |goes |depends |on...? |- |CORRECT |ANSWER✔✔--Activation |Energy.
,Acid |Base |reaction |are |____________. |(speed). |However, |this |does |not |mean |that |an |Acid |
Base |reaction |will |go |to...? |- |CORRECT |ANSWER✔✔--Fast. |
-Completion.
HCl(g) |+H2O--> |H3O+(aq) |+Cl-(aq) |
This |reaction |occurs |______________ |and |only |the |______________ |are |detectable |in |the |
reaction |mixture. |- |CORRECT |ANSWER✔✔--Immediately. |
-Products.
If |you |dissolve |0.1 |mol |HCl |in |1L |solution-immediately |the |pH |= |? |However |if |you |dissolve |0.1 |
mol |acetic |acid |in |1L |solution-immediately |the |pH |=? |- |CORRECT |ANSWER✔✔--1. |
-2.9.
Weak |Acid |Base |Reaction |are |_______ |but |DO |NOT |go |to |___________. |- |CORRECT |
ANSWER✔✔--Fast. |
-Completion.
Rusting-oxidation |of |Iron-tends |to |be |slow |(you |would |have |to |wait |a |while)-but |if |you |leave |it |
long |enough |the |reaction |will...? |- |CORRECT |ANSWER✔✔--Go |to |completion.
The |rate |of |a |reaction |has |NOTHING |to |fo |with |the |position |of |____________. |- |CORRECT |
ANSWER✔✔--Equilibrium. |
(How |fast |a |reaction |is |has |nothing |to |do |with |how |far |it |goes.)
A |rate |is |a |________ |in |something |per |unit |of |time. |e.g. |speed |is |miles |per |hour |(miles/hr |or |
mph) |or |km/s. |- |CORRECT |ANSWER✔✔--Change.
, If |you |travel |120 |miles |in |2 |hours, |your |rate |is...? |
A. |120 |mph |
B. |60 |mph |
C. |240 |mph |
D. |It |depends |
*Change |in |distance |traveled |/ |change |in |time. |
Delta |Distance |/ |Delta |time. |- |CORRECT |ANSWER✔✔--B. |
(120 |miles |/ |2 |hours |= |60 |mph).
Reaction |Rates: |
What |is |changing |per |unit |of |time? |- |CORRECT |ANSWER✔✔--The |amount |of |the |reactant |or |
product |(moles!).
Most |reactions |take |place |in |____________. |So |we |can |use |molarity |(M, |mol/L) |as |the |amount
|of |reactant |(or |product). |- |CORRECT |ANSWER✔✔--Solutions.
The |rate |of |a |reaction |is...? |- |CORRECT |ANSWER✔✔--the |change |in |concentration |per |unit |of |
time |M/times |(or |mol/L.s). |
-Delta[x]/Delta |t.
If |the |concentration |of |a |reactant |X, |[X] |changed |from |1.5M |to |0.5 |M |over |10 |seconds, |the |
rate |Ould |be |change |in |concentration |/ |change |in |time, |or |Delta |[X] |/ |Delta |t. |
A. |1.5 |mol/L.s |
B. |0.15 |mol/L.s |
C. |1.0 |mol/L.s |
D. |0.1 |mol/L.s |
What |is |the |rate |in |M/s |(or |mol/L.s)? |- |CORRECT |ANSWER✔✔--D |
COMPLETE SOLUTIONS
What |do |you |know |about |reactions? |(make |a |list) |- |CORRECT |ANSWER✔✔--Atoms |are |
conserved. |They |are |only |re-arranged. |
-Properties |of |products |are |emergent |(not |a |mixture |of |the |reactants |properties). |
-Reactions |can |be |classified |by |the |type |of |reaction |(how |it |occurs). |
-Reactions |are |always |accompanied |by |an |energy |change |(can |be |exo |and |endo) |that |results |
from |changed |in |interactions |(bonds |and |IMFs) |in |the |reactants |and |products. |
-Reactions |are |always |accompanied |by |an |entropy |change.
What |are |the |two |main |typed |of |reactions? |- |CORRECT |ANSWER✔✔--Acid-base |
-Redox |
*Always |accompanied |by |a |changed |in |entropy.
Can |you |predict |the |properties |of |products |if |you |know |the |properties |of |the |reactants? |
A. |Yes
B. |No |
C. |It |depends |
D. |I |dont |know |- |CORRECT |ANSWER✔✔--B |
*Properties |include |smell, |melting |point, |boiling |point, |and |color.
For |the |reaction: |A+B-->C
If |A |is |yellow |and |B |is |blue, |what |color |is |C? |
A. |Yellow |
B. |Blue |
,C. |Green
D. |I |dont |know |- |CORRECT |ANSWER✔✔--D
*React |NOT |mix. |C |= |completely |new |product.
What |thermodynamic |function |tells |you |about |how |far |a |reaction |will |"go"? |
A. |Delta |H |
B. |Delta |S |(system) |
C. |Delta |G |
D. |None |of |these |- |CORRECT |ANSWER✔✔--C
*If |(+) |will |NOT |happen. |
*If |(-) |WILL |happen.
What |thermodynamic |function |tells |you |about |how |fast |a |reaction |will |"go"? |
A. |Delta |H |
B. |Delta |S |(system) |
C. |Delta |G |
D. |None |of |these |- |CORRECT |ANSWER✔✔--D |
*Delta |H |= |energy |change |/ |only |heat. |
*Delta |S |= |Number |of |possible |arrangements |in |system. |
*Delta |G |= |How |far |the |reaction |will |go.
Reactions |can |"go" |both |____________ |and |_____________! |The |sign |of |__________ |will |tell |
you |whether |a |reaction |will |go |forwards |or |backwards. |- |CORRECT |ANSWER✔✔--Forwards |and
|Backwards. |
-Delta |G.
How |fast |a |reaction |goes |depends |on...? |- |CORRECT |ANSWER✔✔--Activation |Energy.
,Acid |Base |reaction |are |____________. |(speed). |However, |this |does |not |mean |that |an |Acid |
Base |reaction |will |go |to...? |- |CORRECT |ANSWER✔✔--Fast. |
-Completion.
HCl(g) |+H2O--> |H3O+(aq) |+Cl-(aq) |
This |reaction |occurs |______________ |and |only |the |______________ |are |detectable |in |the |
reaction |mixture. |- |CORRECT |ANSWER✔✔--Immediately. |
-Products.
If |you |dissolve |0.1 |mol |HCl |in |1L |solution-immediately |the |pH |= |? |However |if |you |dissolve |0.1 |
mol |acetic |acid |in |1L |solution-immediately |the |pH |=? |- |CORRECT |ANSWER✔✔--1. |
-2.9.
Weak |Acid |Base |Reaction |are |_______ |but |DO |NOT |go |to |___________. |- |CORRECT |
ANSWER✔✔--Fast. |
-Completion.
Rusting-oxidation |of |Iron-tends |to |be |slow |(you |would |have |to |wait |a |while)-but |if |you |leave |it |
long |enough |the |reaction |will...? |- |CORRECT |ANSWER✔✔--Go |to |completion.
The |rate |of |a |reaction |has |NOTHING |to |fo |with |the |position |of |____________. |- |CORRECT |
ANSWER✔✔--Equilibrium. |
(How |fast |a |reaction |is |has |nothing |to |do |with |how |far |it |goes.)
A |rate |is |a |________ |in |something |per |unit |of |time. |e.g. |speed |is |miles |per |hour |(miles/hr |or |
mph) |or |km/s. |- |CORRECT |ANSWER✔✔--Change.
, If |you |travel |120 |miles |in |2 |hours, |your |rate |is...? |
A. |120 |mph |
B. |60 |mph |
C. |240 |mph |
D. |It |depends |
*Change |in |distance |traveled |/ |change |in |time. |
Delta |Distance |/ |Delta |time. |- |CORRECT |ANSWER✔✔--B. |
(120 |miles |/ |2 |hours |= |60 |mph).
Reaction |Rates: |
What |is |changing |per |unit |of |time? |- |CORRECT |ANSWER✔✔--The |amount |of |the |reactant |or |
product |(moles!).
Most |reactions |take |place |in |____________. |So |we |can |use |molarity |(M, |mol/L) |as |the |amount
|of |reactant |(or |product). |- |CORRECT |ANSWER✔✔--Solutions.
The |rate |of |a |reaction |is...? |- |CORRECT |ANSWER✔✔--the |change |in |concentration |per |unit |of |
time |M/times |(or |mol/L.s). |
-Delta[x]/Delta |t.
If |the |concentration |of |a |reactant |X, |[X] |changed |from |1.5M |to |0.5 |M |over |10 |seconds, |the |
rate |Ould |be |change |in |concentration |/ |change |in |time, |or |Delta |[X] |/ |Delta |t. |
A. |1.5 |mol/L.s |
B. |0.15 |mol/L.s |
C. |1.0 |mol/L.s |
D. |0.1 |mol/L.s |
What |is |the |rate |in |M/s |(or |mol/L.s)? |- |CORRECT |ANSWER✔✔--D |
