Slide 1 / 84 1 Objects can possess energy as: (a) endothermic - PDF document

Slide 1 / 84 1 Objects can possess energy as: (a) endothermic energy (b) potential energy (c) kinetic energy a only A b only B C c only a and c D b and c E Slide 2 / 84 2 The internal energy of a system A is the sum of the kinetic energy of all of its components is the sum of the rotational, vibrational, and translational B energies of all of its components refers only to the energies of the nuclei of the atoms of the C component molecules is the sum of the potential and kinetic energies of the D components E none of the above Slide 3 / 84 3 Which one of the following conditions would always result in an increase in the internal energy of a system? A The system loses heat and does work on the surroundings. B The system gains heat and does work on the surroundings. C The system loses heat and has work done on it by the surroundings. D The system gains heat and has work done on it by the surroundings. E None of the above is correct.

Slide 4 / 84 4 The value of ΔE for a system that performs 111 kJ of work on its surroundings and gains 89 kJ of heat is __________ kJ. A -111 B -200 C 200 D -22 E 22 Slide 5 / 84 5 The value of ΔE for a system that performs 13 kJ of work on its surroundings and loses 9 kJ of heat is __________ kJ. A 22 B -22 C 4 D -4 E -13 Slide 6 / 84 6 Calculate the value of ΔE in joules for a system that loses 50 J of heat and has 150 J of work performed on it by the surroundings. A 50 B 100 C -100 D -200 E 200

Slide 7 / 84 7 The change in the internal energy of a system that absorbs 2,500 J of heat and that does 7,655 J of work on the surroundings is __________ J. A 10,155 B 5,155 C -5,155 D -10,155 E 1.91 x107 Slide 8 / 84 8 The change in the internal energy of a system that releases 2,500 J of heat and that does 7,655 J of work on the surroundings is __________ J. A -10,155 B -5,155 C -1.91x107 D 10,155 E 5,155 Slide 9 / 84 9 When a system __________, ΔE is always negative. A absorbs heat and does work B gives off heat and does work C absorbs heat and has work done on it D gives off heat and has work done on it E none of the above is always negative.

Slide 10 / 84 10 Of the following, which one is a state function? A H B q C w D heat E none of the above Slide 11 / 84 11 Which one of the following is an endothermic process? A ice melting B water freezing C boiling soup D Hydrochloric acid and barium hydroxide are mixed at 25 °C: the temperature increases. E Both A and C Slide 12 / 84 12 Which one of the following is an exothermic process? A ice melting B water evaporating C boiling soup D condensation of water vapor E Ammonium thiocyanate and barium hydroxide are mixed at 25 °C: the temperature drops.

Slide 13 / 84 13 A __________ ΔH corresponds to an __________ process . A negative, endothermic B negative, exothermic C positive, exothermic D zero, exothermic E zero, endothermic Slide 14 / 84 14 A __________ ΔH corresponds to an __________ process. A negative, endothermic B positive, exothermic C positive, endothermic D zero, exothermic E zero, endothermic zero, endothermic Slide 15 / 84 15 For an endothermic process is _____ while ΔH for an exothermic process is _______. A zero, positive B zero, negative C positive, zero D negative, positive E positive, negative

Slide 16 / 84 16 A chemical reaction that absorbs heat from the surroundings is said to be __________ and has a __________ ΔH. A endothermic, positive B endothermic, negative C exothermic, negative D exothermic, positive E exothermic, neutral Slide 17 / 84 17 The reaction 4Al(s) + 3O 2 (g) → 2Al 2 O 3 (s) ΔH° = -3351 kJ is __________, and therefore heat is __________ by the reaction. A endothermic, released B endothermic, absorbed C exothermic, released D exothermic, absorbed E thermoneutral, neither released nor absorbed Slide 18 / 84 18 The molar heat capacity of a compound with the formula C 2 H 6 SO is 88.0 J/mol-K. The specific heat of this substance is __________ J/g-K. A 88.0 B 1.13 C 4.89 D 6.88x10 3 E -88.0

Slide 19 / 84 19 A sample of aluminum metal absorbs 9.86 J of heat, and the temperature of the sample increases from 23.2 °C to 30.5 °C. Since the specific heat capacity of aluminum is 0.90 J/g-K, the mass of the sample is __________ g. A 75 B 1.5 C 65 D 8.1 E 6.6 Slide 20 / 84 20 The specific heat capacity of lead is 0.13 J/g-K. How much heat (in J) is required to raise the temperature of 15g of lead from 22 °C to 37 °C? A 2.0 B -0.13 C 5.8 x10 -4 D 29 E 0.13 Slide 21 / 84 21 The temperature of a 15-g sample of lead metal increases from 22 °C to 37 °C upon the addition of 29.0 J of heat. The specific heat capacity of the lead is __________ J/g-K. A 7.8 B 1.9 C 29 D 0.13 E -29

Slide 22 / 84 22 The ΔH for the solution process when solid sodium hydroxide dissolves in water is 44.4 kJ/mol. When a 13.9-g sample of NaOH dissolves in 250.0 g of water in a coffee-cup calorimeter, the temperature increases from 23.0 °C to __________ °C. Assume that the solution has the same specific heat as liquid water, i.e., 4.18 J/g-K. A 35.2 °C B 24.0 °C C 37.8 °C D 37.0 °C E 40.2 °C Slide 23 / 84 23 An 8.29 g sample of calcium carbonate [CaCO 3 (s)] absorbs 50.3 J of heat, upon which the temperature of the sample increases from 21.1 °C to 28.5 °C. What is the specific heat of calcium carbonate? A 0.63 B 0.82 C 1.1 D 2.2 E 4.2 Slide 24 / 84 24 A sample of iron absorbs 67.5 J of heat, upon which the temperature of the sample increases from 21.5 ° C to 28.5 °C. If the specific heat of iron is 0.450 J/g-K, what is the mass (in grams) of the sample? A 4.3 B 11 C 21 D 1100 E 1200

Slide 25 / 84 25 A 22.44 g sample of iron absorbs 180.8 J of heat, upon which the temperature of the sample increases from 21.1 °C to 39.0 °C. What is the specific heat of iron? A 0.140 B 0.450 C 0.820 D 0.840 E 0.900 Slide 26 / 84 26 When 45 g of an alloy at 100 0 C is dropped into 100.0 g of water at 25°C, the final temperature is 37°C. What is the specific heat of the alloy (J/g o C)? A 9.88 B 48.8 C 0.423 D 1.77 Slide 27 / 84 27 A 50.0-g sample of liquid water at 25.0 C is mixed with 29.0 g of water at 45.0 °C. The final temperature of the water is __________. A 102 B 27.6 C 35.0 D 142 E 32.3

Slide 28 / 84 28 A 6.50-g sample of copper metal at 25.0 °C is heated by the addition of 84.0 J of energy. The final temperature of the copper is _____ °C. The specific heat of copper is 0.38 J/g-K. A 29.9 B 25.0 C 9.0 D 59.0 E 34.0 Slide 29 / 84 29 How much heat is required to melt 1.5 moles of NaCl at its melting point ( D Hfus = 30 kJ/mol) A 1.5 kJ B 15 kJ C 20 kJ D 30 kJ E 45 kJ Slide 30 / 84 30 A substance releases 500 kJ of heat as 25 mol of it condenses from a gas to a liquid . What is the heat of vaporization ( D Hvap) of this substance? A 20 kJ/mol B 25 kJ/mol C 475 kJ/mol D 525 kJ/mol

Slide 31 / 84 31 If you supply 36 kJ of heat, how many moles of ice a 0 o C can be melted, heated to its boiling point and completely boiled away? D Hvap = 40.5 kJ/mol; D Hfus = 6.0 kJ/mol; specific heat for water, C = 0.0753 kJ/mol- o C Slide 32 / 84 32 Given the equation: H 2 O (l) → H 2 O(g) D Hrxn = 40.7 kJ at 100 °C Calculate the mass of liquid water (in grams) at 100 °C that can converted to vapor by absorbing 2.40 kJ of heat. Slide 33 / 84 33 Given the equation: H 2 O (l) → H 2 O(g) D Hrxn = 40.7 kJ at 100 °C Calculate the heat required to convert 3.00 grams of liquid water at 100 °C to vapor.

Slide 34 / 84 34 Based on the following information, which compound has the strongest intermolecular forces? Substance ΔHvap (kJ/mol) Argon (Ar) 6.3 Benzene (C 6 H 6 ) 31.0 Ethanol (C 2 H 5 OH) 39.3 Water (H 2 O) 40.8 Methane (CH 4 ) 9.2 A Argon B Benzene C Ethanol D Water E Methane Slide 35 / 84 35 What amount of heat (in kJ) is required to melt 35.0 g of ice at 0 o C? A 3.09 kJ B 11.7 kJ C 20.9 kJ D 79.1 kJ Specific heat of ice 2.09 J/g- o C Specific heat of water 4.18 J/g- o C 1.84 J/g- o C Specific heat of steam Heat of fusion of water (Hfus) 6.01 kJ/mol Heat of vaporization of water (Hvap) 40.7 kJ/mol Slide 36 / 84 36 What amount of heat (in kJ) is required to completely convert 190.0 g of liquid water at 18 o C to steam at 100.0 o C? A 6.51 kJ B 6.94 kJ C 430 kJ D 559 kJ 2.09 J/g- o C Specific heat of ice 4.18 J/g- o C Specific heat of water Specific heat of steam 1.84 J/g- o C Heat of fusion of water (Hfus) 6.01 kJ/mol Heat of vaporization of water (Hvap) 40.7 kJ/mol