1. Thermochemistry & Phases Test
Phase Changes
Energy transformations
Conservation of Energy
Endothermic/Exothermic reactions
Temperature conversions (memorize K = ºC+ 273)
Heat & Temperature
Heat Flow
Calorimetry problems
Interpret potential energy diagrams
Thermochemical Stoichiometry
(Mole ↔ Energy)
Properties of 3 Phases
Names of Phase Changes
Endothermic/Exothermic Phases Changes
Energy Changes During Phase Changes
Heat of Fusion/Vaporization Calculations
Dynamic Equilibrium During Phase Changes
Vapor Pressure
Boiling (Changes Using Elevation or Pressure)
Interpreting Heating Curves

2. Jeopardy
Thermo 1
Thermo 2
Phase 1
Phase 2
100
200
300
400
500

3. Credits
That’s all folks.
Exit

4. The burning of magnesium involves the conversion of
A.) heat energy to light energy
B.) light energy to heat energy
C.) light energy to chemical energy
D.) chemical energy to light energy

5. D Chemical Energy to Light Energy
Energy is conserved (not created or destroyed) in all chemical reactions. Therefore the light energy that is emitted in this reaction must have come from the chemical energy stored in the bonds for magnesium and oxygen

6. NaOH(s) + H2O(l)  NaOH(aq) + heat
What change occurs when pellets of NaOH are added to water and stirred?
NaOH(s) + H2O(l)  NaOH(aq) + heat
A.) The water temperature increases as chemical energy is converted to heat energy.
B.) The water temperature increases as heat energy is stored as chemical energy.
C.) The water temperature decreases as chemical energy is converted to heat energy.
D.) The water temperature decreases as heat energy is stored as chemical energy.

7. A. The water temperature increases as chemical energy is converted to heat energy.
Heat is a product. This means that the reaction is exothermic and that energy is released, causing the temperature of the water to increase as it absorbs this heat energy. The heat energy is transformed from the chemical energy stored in the substances bonds.

8. The average kinetic energy of water molecules is greatest in which of these samples?
A.) 10 g of water at 35°C
B.) 10 g of water at 55°C
C.) 100 g of water at 25°C
D.) 100 g of water at 45°C

9. B. 10 g of water at 55°C
Temperature is the measure of a samples average kinetic energy. The sample with the highest temperature must also have the highest kinetic energy. Kinetic energy and temperature do not rely on the amount of sample (mass).

10. Solid X is placed in contact with solid Y
Solid X is placed in contact with solid Y. Heat will flow spontaneously from X to Y when
A.) X is 20oC and Y is 20oC
B.) X is 10oC and Y is 5oC
C.) X is -25oC and Y is -10oC
D.) X is 25oC and Y is 30oC

11. B. X is 10oC and Y is 5oC
Heat energy naturally flows from hot to cold (high temperature to low temperature.

12. Which Celcius temperature is equivalent to 300 K?
A.) 0 ºC
B.) 27 ºC
C.) 300 ºC
D.) 573 ºC

13. B. 27 ºC K = C + 273 *You Must Memorize This Formula* 300 K = °C + 273
°C = 27

14. The specific heat of silver is 0. 24 J/gºC
The specific heat of silver is 0.24 J/gºC. How much heat is needed to warm 4.37 g of silver from 25.0ºC to 27.5ºC?
A.) 2.62 J
B.) 0.14 J
C.) 45.5 J
D.) J

15. A. 2.62 J Q = mcΔT Q = (4.37 g)(0.24 J/g°C)(27.5 °C – 25.0 °C)
Q = 2.62 J
This reaction is endothermic because q is positive

16. How much energy is released when 36
How much energy is released when 36.0 grams of steam condenses into liquid water?
A.) 22.0 kJ
B.) 81.4 kJ
C.) 195 kJ
D.) 1580 kJ

17. B 81.4 kJ Condensing is the opposite of vaporization Q = mHv
Q = (36.0 g)(2260 J/g)
Q = 81,360 J

18. What amount of heat is required to completely melt a 29
What amount of heat is required to completely melt a gram sample of H2O(s) at 0ºC?
A.) 334 J
B.) 2260 J
C.) 1.00 × 103 J
D.) 1.00 × 104 J

19. D 1.00 × 104 J Melting is also known as fusion Q = mHf
Q = (29.95 g)(334 J/g)
Q = 10,003 J

20. Which arrow represents the potential energy of the reactants?
Given the potential energy diagram of a chemical reaction: (see image)
Which arrow represents the potential energy of the reactants?
A.)
B.)
C.)
D.)

21. B A = Activation Energy B = Reactants C = Activated Complex
D = Products

22. In a potential energy diagram, the difference between the potential energy of the products and the potential energy of the reactants is equal to the
A.) heat of reaction
B.) entropy of the reaction
C.) activation energy of the forward reaction
D.) activation energy of the reverse reaction

23. A heat of reaction
ΔH = Hproducts – Hreactants

24. Calculate the energy required to produce 7 moles of Cl2O7
2 Cl2 + 7 O kJ  2 Cl2O7
Calculate the energy required to produce 7 moles of Cl2O7
A.) kJ
B.) kJ
C.) kJ
D.) kJ

25. D kJ
2 Cl2 + 7 O kJ  2 Cl2O7
7 = X

26. Two basic properties of the gas phase are
A.) a definite shape and a definite volume
B.) a definite shape but no definite volume
C.) no definite shape but a definite volume
D.) no definite shape and no definite volume

27. D no definite shape and no definite volume
Solid = definite shape and definite volume
Liquid = definite volume but no definite shape

28. Which phase change is an exothermic process?
A.) CO2(s)  CO2(g)
B.) NH3(g)  NH3(l)
C.) Cu(s)  Cu(l)
D.) Hg(l)  Hg(g)

29. G L S B NH3(g)  NH3(l) EXOTHERMIC ENDOTHERMIC RELEASES ENERGY
NEEDS ENERGY S

30. A pot of water is brought to a boil
A pot of water is brought to a boil. The temperature of the water when it started to boil was 100.0ºC. What do you expect the thermometer to read after boiling for 15 minutes?
A.) Below 100.0ºC
B.) 100.0ºC
C.) 105.0ºC
D.) 115.0ºC
E.) Above 115.0ºC

31. B ºC
Temperature does not change during a phase change. The heat energy is being converted into potential energy during this phase change, not kinetic energy that would result in a change in temperature.

32. The graph (see image) represents the uniform heating of a substance, starting with the substance as a solid below its melting point.
Which line segment represents an increase in potential energy and no change in average kinetic energy?
A) 1
B) 2
C) 3
D) 4
D.) 4
B.) 2
A.) 1
C.) 3

33. B BC
Kinetic energy is seen by a change in temperature such as AB, CD, and EF. Potential energy changes on the plateaus, where the temperature does not change, such as BC and DE

34. The graph represents the uniform cooling of a substance, starting with the substance as a gas above its boiling point. During which interval is the substance completely in the liquid phase?
A.) AB
B.) BC
C.) CD
D.) DE

35. C CD AB = Gas BC = Condensation (gas and liquid) CD = Liquid
DE = Melting
(liquid and solid)
EF = solid

36. As the temperature of a liquid increases, its vapor pressure
A.) decreases
B.) increases
C.) remains the same

37. B increases
As the temperature increases so does the kinetic energy of the particles. An increase in the pressure pushing up is caused.

38. As the pressure on the surface of a liquid decreases (atmospheric pressure), the temperature at which the liquid will boil
A.) decreases
B.) increases
C.) remains the same

39. A decreases
Substances boil when the vapor pressure (up) is equal to the atmospheric pressure (down). If the pressure pushing down is lessened then less pressure up is needed to reach the boiling point. This means that a lower temperature is needed to get the necessary vapor pressure.

40. At which temperature will equilibrium exist for the system below?
H2O(s) ↔ H2O(l)
A.) 0 K
B.) 100 K
C.) 273 K
D.) 373 K

41. C K
Solid and liquid exist at the melting/freezing point, 0 °C for water.
K = °C + 273
K = 0 °C+ 273
K = 273

42. Category 4 $500
Answer

43. Category 4 $500
Question?