Name: ______Period: ______

Unit 12: Energy and Thermodynamics- Funsheet Packet

Part A: Reaction Diagrams

1)Answer the following questions based on the potential energy diagram shown:

  1. This graph represent an (endothermic / exothermic) reaction. (circle your answer)
  2. Label the reactants, products, and activated complex.
  3. Draw a dashed line on the diagram to indicate a potential energy curve for the reaction if a catalyst is added.
  4. Determine the heat of reaction, ΔH, (enthalpy change) for this reaction. ______
  5. Determine the activation energy, Ea for this reaction. ______
  6. How much energy is required for this reaction to occur? ______
  7. What is the ΔH for the reverse reaction? ______
  8. What is the activation energy for the reverse reaction?______

2)Answer the following questions based on the potential energy diagram shown here:

  1. This graph represent an (endothermic / exothermic) reaction. (circle your answer)
  2. Label the reactants, products, and activated complex.
  3. Draw a dashed line on the diagram to indicate a potential energy curve for the reaction if a catalyst is added.
  4. Determine the heat of reaction, ΔH, (enthalpy change) for this reaction. ______
  5. Determine the activation energy, Ea for this reaction. ______
  6. How much energy is required for this reaction to occur? ______
  7. What is the ΔH for the reverse reaction? ______
  8. What is the activation energy for the reverse reaction?______

3)Sketch a potential energy curve below that is represented by the following values of ΔH and Ea (activation energy). You may make up appropriate values for the y-axis (potential energy). ΔH = +45 kJ and Ea = 100 kJ

4)Sketch a potential energy curve of the reaction between carbon monoxide and nitrogen monoxide at an initial energy of 230 kJ. The reaction requires 134 kJ of energy then releases 226 kJ of heat energy.

Part B: Phases Changes- Include units and show ALL WORK! q= mcΔT q= m x ∆Hfus q= m x ∆Hvap

1)An igloo is made of 224 blocks of ice at 0°C, each with a mass of 12.0 kg. How much heat must be gained by the ice to melt the entire igloo? (hf of water = 3.35 x 105 J/kg)

2)How much energy (in calories and in Joules) will it take to raise the temperature of 75.0 g of water from 20.0 to 55.0 oC? ( Specific Heat = 1 cal / ( g oC ) and 4.184 J / ( g oC )

3)350 J are released as ice ( Specific Heat = 2.1 J / (g oC) ) cools from - 5.0 oC to -32 oC. What is the mass of ice?

4)By January, the 3.0 kg of water in the birdbath in the backyard has frozen to a temperature of -7.0°C. As the season changes, how much heat must be added to the water to make it a comfortable 25°C for the birds? (cwater = 4187 J/kg°C) (cice = 2090 J/kg°C) (hf of water = 3.35 x 105 J/kg)

5)Consider a 0.63-kg sample of metal at room temperature of 20°C. The addition of 6.42 x 105 J increases its temperature to its melting point (782°C). An additional 5.94 x 104 J causes the sample to completely liquefy. (a) What is the specific heat capacity of the sample? (b) What is the heat of fusion of the metal?

6)How much energy would be reqired to melt 10.0 g of ice ( Specific Heat = 2.1 J / (g oC) ) at 0 oC, warm the resulting liquid ( Specific Heat = 4.184 J / ( g oC ) ) to 100 oC, and change it to steam at 100 oC?(Hfus = 6.01 KJ/mol; Hvap = 40.7 KJ/mol; )

7)A 63.0 g piece of aluminum (Specific Heat = 0.215 cal / (g oC) ) at 25.0 oC is warmed by the addition of 325 calories of energy. Find the final tempearture of the aluminum.

8)How many grams of steam could be condensed at 100 o C with the removal of 307 KJ of energy? Hvap = 40.7 KJ/mol

Part C: Calorimetry- Include units and show ALL WORK!

1)To cool her 0.200-kg cup of 75.0°C hot chocolate (mostly water), Heidi drops a 0.0300-kg ice cube at 0°C into her insulated foam cup. What is the temperature of the hot chocolate after all the ice is melted? (hf of water = 3.35 x 105 J/kg)

2)A piece of metal weighing 59.047 g was heated to 100.0 °C and then put it into 100.0 mL of water (initially at 23.7 °C). The metal and water were allowed to come to an equilibrium temperature, determined to be 27.8 °C. Assuming no heat lost to the environment, calculate the specific heat of the metal.

3)In a coffee-cup calorimeter, 100.0 g of H2O and 100.0 mL of HCl are mixed. The HCl had an initial temperature of 44.6 oC and the water was originally at 24.6 oC. After the reaction, the temperature of both substances is 31.3 oC.

  1. Was the reaction exothermic or endothermic? Explain.
  1. Calculate how much heat the water lost or gained.

4)Calculate the specific heat of a metal if adding 100.0 g of the metal at 50.0 C is added to 50.0g of water at 20.00 C results in a final temperature of 23.10 C. The cwater is 4.184 J/g C.

5)A 2.50 g sample of zinc is heated, then placed in a calorimeter containing 65.0 g of water. Temperature of water increases from 20.00 oC to 22.50 oC. The specific heat of zinc is 0.390 J/goC. What was the initial temperature of the zinc metal sample? (final temperatures of zinc and water are the same)

6)A 13.5 g sample of gold is heated, then placed in a calorimeter containing 60.0 g of water. Temperature of water increases from 19.00 oC to 20.00 oC. The specific heat of gold is 0.130 J/goC. What was the initial temperature of the gold metal sample?

Part D: Hess’s Law- Include units and show ALL WORK!

1)Calculate the heat of reaction for: PbCl2 (s) + Cl2(g) PbCl4 (l) ∆H = ?

Given the following:Pb (s) + Cl2(g) PbCl2 (s) ∆ H = - 359.40 kJ

Pb (s) + 2 Cl2(g) PbCl4 (l) ∆ H = - 329.30 kJ

2)From the following heats of reaction: 2 SO2(g) + O2(g) 2 SO3(g) ΔH = – 196.00 kJ 2 S(s) + 3 O2(g) 2 SO3(g) ΔH = – 790.00 kJ

Calculate the heat of reaction for: S(s) + O2(g) SO2(g) ΔH = ? kJ

3)Given the following equations: 4 NH3(g) + 5 O2(g)→ 4 NO(g) + 6 H2O(l)ΔH° = -1170 kJ

4 NH3(g) + 3 O2(g)→ 2 N2(g) + 6 H2O(l) ΔH° = -1530 kJ

Using these two equations, determine the heat of formation, ΔHf, for nitrogen monoxide. N2 (g) + O2 (g)  2NO (g)

4)From the following heats of reaction:2 H2 (g) + O2 (g)  2 H2O (g)ΔH = - 483.6 kJ

3 O2 (g)  2 O3 (g) ΔH = +284.6 kJ

Calculate the heat of the reaction for: 3 H2 (g) + O3 (g)  3 H2O (g)

5)Given the following data: N2 (g) + O2 (g)  2 NO (g) ΔH = + 180.7 kJ

2 NO (g) + O2 (g)  2 NO2 (g)ΔH = - 113.1 kJ

2 N2O (g)  2 N2 (g) + O2 (g) ΔH = - 162.3 kJ

Use Hess’s law to calculate ΔHfor the following reaction: N2O(g) + NO2 (g)  3 NO (g)

6)Given the following data: H2 (g) + ½ O2 (g)  H2O (l) ΔH = -285.8 kJ

2 N2O5 (g) + 2 H2O (l)  4HNO3 (l)ΔH = - 153.2 kJ

½ N2 (g) + 3/2 O2 (g) + ½ H2 (g)  HNO3 (g) ΔH = - 174.1 kJ

Use Hess’s law to calculate ΔHfor the following reaction: 2 N2 (g) + 5 O2 (g)  2 N2O5 (g)

7)Given the following data: C(s) + O2 (g)  CO2 (g) ΔH = - 393.5 kJ

H2 (g) + ½ O2 (g)  H2O(g)ΔH = - 285.8 kJ

C5H12 (g) + 8 O2 (g) 5CO2 (g) + 6 H2O (g) ΔH = - 3536 kJ

Use Hess’s law to calculate ΔHfor the following reaction: 5 C(s) + 6 H2 (g)  C5H12 (g)

8)Given the following data: CO(g) + SiO2 (s)  SiO (g) + CO2 (g) ΔH = + 520.9 kJ

3 SiO2 (s) + 2N2O (g) + 8 CO (g)  8CO2 (g) + Si3N4 (s)ΔH = - 461.1 kJ

Use Hess’s law to calculate ΔHfor the following reaction: 5CO2 (g) + Si3N4 (s)  3 SiO (g) + 2 N2O (g) + 5 CO (g)

Part E: Heat of Formation- Include units and show ALL WORK!

1)The standard heats of formation of HCl (g) and HBr (g) are -92.0 kJ/mol and -36.4 kJ/mol respectively. Diatomic gases have a heat of formation of 0 kJ Using this information, calculate ΔH for the following reaction: Cl2 (g) + 2 HBr (g)→ 2 HCl (g) + Br2 (g)

2)Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction: 2 LiOH(s) + CO2(g) Li2CO3(s) + H2O(l)

3)Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction: 2 Cl2(g) + 2 H2O(l) 4 HCl(g) + O2(g)

4)Calculate ΔHof(kJ) for the following reaction from the listed standard enthalpies of formation: 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g)

5)The standard enthalpy of formation of propane, C3H8, is -103.6 kJ/mole. Calculate the heat of combustion of C3H8. The heats of formation of CO2(g) and H2O(l) are -394 kJ/mole and -285.8 kJ/mole respectively. Diatomic molecules have a heat of formation of 0 kJ/mole. C3H8 + 5O2  3CO2 + 4H2O

6)The standard enthalpy of formation of propyne, C3H4, is +185.4 kJ/mole. Calculate the heat of combustion of C3H4. The heats of formation of CO2(g) and H2O(l) are -394 kJ/mole and -285.8 kJ/mole respectively. C3H4 + 4O2  3CO2 + 2H2O

7)The standard enthalpy of formation of ethanol, C2H5OH, is -277.7 kJ/mole. Calculate the heat of combustion of C2H5OH. The heats of formation of CO2(g) and H2O(l) are -394 kJ/mole and -285.8 kJ/mole respectively. C2H5OH + 3O2  2CO2 + 3H2O

Part F: Stoichiometry- Include a balanced chemical equation, units, and show ALL WORK!

1)If 245 L of chlorine gas reacts with excess phosphorous trichloride, what amount of energy is released? _____PCl3(g) + _____Cl2(g) → _____PCl5(g) ΔH = −87.9 kJ

2)If 300.0 kJ of energy is absorbed, what volume of oxygen gas is produced? _____SO3 (g) → _____SO2 (g) + O2(g) ΔH = 197.9 kJ

3)How many kilojoules are given off when 17.8 mol of CH4 (g) combusts? _____CH4(g) + _____O2(g) → _____CO2 (g) + _____H2O(ℓ) ΔH = −890.1 kJ

4)How many kilojoules are absorbed when 0.772 mol of N2 (g) reacts? _____N2(g) + _____NO(g) → _____N2O(g) ΔH = 73.8 kJ

5)How many kilojoules are absorbed when 23.09 mol of C6H6(ℓ) are formed? _____C(s) + _____H2(g) → C6H6(ℓ) ΔH = 49.0 kJ

6)How many kilojoules are given off when 8.32g of Mg react? _____Mg(s) + _____O2 (g) → ____MgO(s) ΔH = −1,213 kJ

7)Glucose is the main fuel metabolized in animal cells:C6H12O6 + 6O2 → 6CO2 + 6H2O ΔH = −2,799 kJ How much energy is given off when 100.0 g of C6H12O6 react?

8)Given the thermochemical equation: ____Al(s) + ___Fe2O3 (s) → ____Al2O3 (s) + ____Fe(s) ΔH = −850.2 kJ
How much energy is given off when 288 g of Fe are produced?

9)Given the thermochemical equation: ____CO2(g) → ____CO(g) + ____O2 (g) ΔH = 566 kJ. How much energy is absorbed when 85.2 g of CO2 are reacted?

10)NaHCO3decomposes when exposed to heat. What mass of NaHCO3 is decomposed by 256 kJ?

_____NaHCO3(s) → ____Na2CO3 (s) + ____CO2(g) + H2O(ℓ) ΔH = 91.5 kJ.

Part G: Vocabulary and Concepts- Answer the following questions using your notes.

1)Fill in the blanks: When the products have ______potential energy than the reactants, the ΔH values is positive. When the products have ______potential energy than the reactants, the ΔH values is negative.

2)What is Energy? ______

3)How is average kinetic energy measured? ______

4)In your own words, what is thermodynamics?

5)What is heat? What direction does heat flow? What letter represents heat?

6)Define system and surroundings in your own words.

7)Indicate whether the following are endothermic (ENDO) or exothermic (EXO):

  1. ______The burning of wood to produce a hot flame.
  2. ______4Fe(s) + 3O2(g)  2Fe2O3(s) + energy
  3. ______A test tube that feels cold to the touch after two substances have been mixed.
  4. ______C(s) + 2 F2(g) CF4(g)ΔHo = -680 kJ
  5. ______Melting
  6. ______Vaporization
  7. ______Sublimation
  8. ______Deposition
  9. ______Solidification
  10. ______Condensation

8)Describe how the activation energy of a reaction affects the overall rate of the chemical reaction. ______

9)What is a reversible reaction? ______

10)What is an activated complex? ______

11)A ______speeds up a chemical reaction by lowing the ______energy.

12)What is enthalpy? ______

13)What is Hess’s Law? ______

14)Compare and contrast catalysts and inhibitors.

15)Circle the correct answer: If something is (endothermic/exothermic) more heat goes from surroundings into the system. The ΔH value is (positive/negative).

16)Circle the correct answer: If something is (endothermic/exothermic) more heat goes from the system into the surroundings. The ΔH value is (positive/negative).

17)What law explains that during a chemical reaction mass is not created or destroyed just rearranged to create new products? ______

18)What law explains that energy is not created or destroyed just transferred between system and surroundings? ______

19)What is latent heat of fusion?

20)What is latent heat of vaporization?

21)True or false: Temperature always changes during a phases change. ______

22)What is specific heat?

23)Using specific heat explain why we use metals for things like pots and pans and covalent compounds for insulators.

24)What does this symbol mean: Δ? ______

25)What is calorimetry?

26)In calorimetry, where does the heat gained or lost by the system go?

27)What are we measuring during a calorimetry experiment? ______

28)What is one practical use or everyday use of calorimetry?

29)What is heat of formation?

30)What does this symbol mean: ∑? ______

31)Draw and label the set up for a simple calorimeter.


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