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Chemistry
10thgrade
AP Chemistry: Thermochemistry & Thermodynamics
51 questions
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- 1. Multiple ChoiceThe heat content of a system at constant pressure is calledentropyenthalpyheatenergy
- 2. Multiple ChoiceThe capacity to do work or transfer heattemperatureenergypowerenthalpy
- 3. Multiple ChoiceThe heat required to raise the temperature of WATER 1∘Ccaloriejoulespecific heatenergy
- 4. Multiple ChoiceFormula for solving specific heat problemsq = mcΔTH = ΔH x molesH = ΔH x gramsproducts - reactants
- 5. Multiple ChoiceThe following graph shows a(n)endothermic reactionexothermic reactionincrease in entropydecrease in entropy
- 6. Multiple ChoiceAn endothermic reaction feels _____ to the touchwarmcool
- 7. Multiple ChoiceWhat type of reaction is shown?reactantsendothermicexothermicproducts
- 8. Multiple ChoiceIn an exothermic process the surrounding looses heat.TrueFalse
- 9. Multiple ChoiceH2 + 2 C + N2 + 270.3 kJ --> 2 HCN
Is this reaction endothermic or exothermic?EndothermicExothermic - 10. Multiple ChoiceIs the combustion of gasoline endothermic or exothermic?EndothermicExothermic
- 11. Multiple ChoiceIn a laboratory experiment a student was using Styrofoam cups and foil to reduce the energy lost during an exothermic reaction. The reaction constantly had a temperature probe in it. Towards the end of the reaction the student noticed the temperature in the cups was going down (opposite what they thought is should). The student concluded that the energy was destroyed within the system. This student's reasoning violates what law?Law of Conservation of MassLaw of EnthalpyFirst Law of ThermodynamicsLaw of Heat Transfer
- 12. Multiple ChoiceWhich direction does heat flow?hot to coldcold to hot
- 13. Multiple ChoiceA sample of iron receives 50.J of heat energy that raises the temperature of the iron 25.0°C. If iron has a specific heat of .10 J/g°C, what is the mass of the iron sample?25g30g20g50g
- 14. Multiple Choice
A liquid with a specific hear of 1.9 J/gC has 4750 J of energy added to it. The temperature changed from 20 degrees C to 30 degrees C, what is the mass of the liquid?
250 cal
2500g
250 g
2500 cal
- 15. Multiple ChoiceRefer the the following question:
2N2 + 3H2 --> 2NH3 + 46 kJ
How much energy would be produced if only 1 mol of nitrogen was reacted?92 kJ0.143 kJ23 kJ15 kJ - 16. Multiple Choice
Which of the letters (A-D) represents the minimum amount of energy required for the reaction to proceed forward?
A
B
C
D
- 17. Multiple ChoiceWhich of the letters (A-D) represents the potential energy of the products?ABCD
- 18. Multiple Choice(Hess's Law)Calculate the ∆H for the following reaction: 2H2O2 → 2H2O + 1 O2
You are given these two equations:
2H2 + O2 → 2H2O ∆H = -572 kJ
H2 + O2 → H2O2 ∆H = -188 kJ∆H = -948 kJ∆H = -196 kJ∆H = -384 kJ∆H = -188 kJ - 19. Multiple Choice(Hess's Law) Calculate the ∆H for the following reaction:
2CO + 2NO → 2CO2 + N2
You are given these two equations:
2CO + O2 → 2CO2 ∆H = -566.0 kJ
N2 + O2 →2NO ∆H = 180.6 kJ∆H = -385.4 kJ∆H = -746.6 kJ∆H = 385.4 kJ∆H = 746.6 kJ - 20. Multiple ChoiceTemperature is a measure of the...total energy in a substancetotal kinetic energy in a substanceaverage potential energy in a substanceaverage kinetic energy of molecules in a substance
- 21. Multiple Choice
When thermal energy is added to a substance, the substance's particles move:
More rapidly at an increased distance from each other.
More rapidly with less distance between each other.
More slowly with a greater distance between each other.
More slowly with a reduced distance between each other.
- 22. Multiple ChoiceHeat transfer by conduction occurs when...particles bump into each otherlarge numbers of atoms move from place to placeatoms give off heat in the form of electromagnetic waveselectromagnetic waves travel from place to place through a vacuum
- 23. Multiple ChoiceHeat transfer by convection occurs when...electrons bump into other electronslarge numbers of atoms move from place to placeatoms give off heat in the form of electromagnetic waveselectromagnetic waves travel from place to place through a vacuum
- 24. Multiple ChoiceA substance with a high specific heat:Is always extremely hot.Requires a lot of energy to become hot.Is not heavy.Does not requires a lot of energy to become hot.
- 25. Multiple ChoiceThe second law of thermodynamics states that entropy of a system tends to ______________.increasedecreasestay constantfluctuate wildly
- 26. Multiple ChoiceThe first law of thermodynamics states that energy iscreateddestroyedconservedcreated and destroyed
- 27. Multiple ChoiceWhich law of thermodynamics states that absolute zero cannot be reached?1st2nd3rd
- 28. Multiple ChoiceWhat is "Entropy"?The tendency of objects to warm upThe tendency of energy to spread outThe tendency of energy to make heatThe tendency of objects to do work
- 29. Multiple Choice
A substance of mass 2.0 kilograms is originally in the solid state. The graph below represents the temperature of the substance as heat is added to it. During which interval is the average kinetic energy of the molecules of the substance unchanged?
BC
CD
AB
AC
- 30. Multiple Choice
Which phase change is exothermic?
H 2O( l) → H 2O( s)
H 2O( l) → H 2O( s)
H 2O( l) → H 2O( g)
H 2O( s) → H 2O( g)
- 31. Multiple ChoiceWhat phase change brings an increase in entropy?g->sl->sl->gg->l
- 32. Multiple ChoiceAs NaCl dissolves according to the equation
NaCl(s) → Na+(aq) + Cl-(aq), the entropy of the systemIncreasesDecreasesRemains the same - 33. Multiple ChoiceSolid magnesium dissolves in a hydrochloric acid, releasing hydrogen gas and heat from a solution of magnesium chloride. What is the sign on ΔH for this reaction?Negative because it is exothermicNegative because it is endothermicPositive because it is exothermicPositive because it is endothermic
- 34. Multiple ChoiceWhen ammonium nitrate dissolves in water, the solution gets cold. Which is true?Reaction is ENDOTHERMIC with positive ΔHReaction is ENDOTHERMIC with -ΔHReaction is EXOTHERMIC with a -ΔHReaction is EXOTHERMIC with +ΔH
- 35. Multiple ChoiceA reaction has a positive ΔH and a positive ΔS. Which of the following is true?It will be spontaneous at all temperatures.It will be nonspontaneous at all temperatures.It will be spontaneous at low temperatures.It will be spontaneous at high temperatures.
- 36. Multiple ChoiceTrue/False: The rate of a chemical reaction is unrelated to the spontaneity of the reaction.TrueFalse
- 37. Multiple Choice
At what temperature will a reaction become spontaneous if the change in enthalpy is -192 KJ/mol and the change in entropy is -562 J/mol?
Above 341.6 K
Below 341.6 K
Above .34 K
Below .34 K
- 38. Multiple ChoiceEntropy always increases whenenthalpy decreases.temperature decreases.temperature increases.volume increases.
- 39. Multiple Choice
Predict the entropy change, ΔS.
ΔS = +
ΔS = -
ΔS = 0
ΔS = no change
- 40. Multiple ChoiceWhich 1 g sample will have the highest temperature after the addition of 200 J of energy?H2O(l)H2O(g)CuPb
- 41. Multiple ChoiceA 5.00 gram sample of a metal at 85.0 °C comes in contact with 100.0 grams of water at 25.0 °C. What is the direction of the heat flow and why?Metal to water, since heat flows from low mass to high massWater to metal, since heat flows from high mass to low massMetal to water, since heat flows from high temp. to low temp.Water to metal, since heat flows from low temp. to high temp.
- 42. Multiple ChoiceWhich of the following would have a nonzero enthalpy of formation?Fe(s)Br2(s)O2(g)Hg(l)
- 43. Multiple ChoiceWhich of the following would have a standard enthalpy of formation value of zero?H2O(l)H2O(g)F2(g)O3(g)
- 44. Multiple ChoiceThermodynamically favorable reactions...are very fastoccur only with the addition of workoccur without the addition of workare always exothermic
- 45. Multiple ChoiceThermodynamically favorable reactions tend to go to...low energy and high entropylow energy and low entropyhigh energy and high entropyhigh energy and low entropy
- 46. Multiple ChoiceWhich of the following possesses the greatest amount of entropy?1 mol of Ar(g) at 0.5 atm and 298 K1 mol of Ar(g) at 0.5 atm and 400 K2 mol of Ar(g) at 0.5 atm and 400 K2 mol of Ar(g) at 1 atm and 400 K
- 47. Multiple ChoiceThe reaction with the largest increase in entropy is...CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)CH4(l) + 2O2(g) → CO2(g) + 2H2O(l)CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)CH4(l) + 2O2(g) → CO2(g) + 2H2O(g)
- 48. Multiple Choice2N2O5 --> 4NO2 + O2
ΔHf
N2O5 11.289 kJ/mol
NO2 33.150 kJ/mol
O2 0 kJ/mol
ΔHreaction = ?110.022 kJ10.572 kJ121.311 kJ21.861 kJ - 49. Multiple Choice
If an equilibrium constant, K>1 , what wll be the sign of the Gibbs Free Energy
Δ G = 0
Δ G < 0
Δ G > 0
- 50. Multiple Choice
For a particular chemical reaction ΔH = 5.5 kJ and ΔS = -25 J/K
Under what temperature conditions is the reaction thermodynamically favored?
When T < -220 K
When T < 220 K
The reaction is spontaneous at all temperatures.
The reaction is not spontaneous at any temperatures.
- 51. Multiple Choice
The Ksp for a very insoluble salt is 4.2 x 10-47 at 298 K. What is ΔG° for the dissolution of the salt in water?
-265 kJ/molrxn
+265 kJ/molrxn
-115 kJ/molrxn
+115 kJ/molrxn
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