Thermochemistry - Multiple Choice
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LONG EXAM IN CHEMISTRY Thermochemistry Name: _____________________________ Year and Section: _________ Multiple Choice Direction: Encircle the correct answer 1) Which of the following is the definition of internal energy of a system? a. It is the sum of the kinetic energy of all of its components b. It is the sum of the rotational, vibrational, and translational energies of all of its components c. It refers only to the energies of the nuclei of the atoms of the component molecules d. It is the sum of the potential and kinetic energies of the components 2) 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. 3) The value of ΔE for a system that performs 111 kJ of work on its surroundings and gains 89 kJ. What is the heat of the system in kilojoules? a. -111 b. -200 c. 200 d. -22 4) When ΔE is always negative then what happens in the system? 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 5) Of the following, which one is a state function? a. H b. q c. w d. heat 6) Which one of the following is an endothermic process? a. ice melting
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Transcript of Thermochemistry - Multiple Choice
LONG EXAM IN CHEMISTRYThermochemistry
Name: _____________________________Year and Section: _________
Multiple ChoiceDirection: Encircle the correct answer
1) Which of the following is the definition of internal energy of a system? a. It is the sum of the kinetic energy of all of its components b. It is the sum of the rotational, vibrational, and translational energies of all of its components c. It refers only to the energies of the nuclei of the atoms of the component molecules d. It is the sum of the potential and kinetic energies of the components
2) 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.
3) The value of ΔE for a system that performs 111 kJ of work on its surroundings and gains 89 kJ. What is the heat of the system in kilojoules?
a. -111 b. -200 c. 200 d. -22
4) When ΔE is always negative then what happens in the system?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
5) Of the following, which one is a state function? a. H b. q c. w d. heat
6) 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
7) Which one of the following is an exothermic process? a. ice melting b. water evaporating c. boiling soup d. condensation of water vapor
8) 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
9) 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. What is the specific heat capacity of the lead in J/g-K?
A) 7.8 B) 1.9 C) 29 D) 0.13
10) An 8.29 g sample of calcium carbonate [CaCO3(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) .63 B) .82 C) 1.1 D) 2.2
11) 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
12) A 50.0-g sample of liquid water at 25.0 C is mixed with 29.0 g of water at 45.0 °C. What is the final temperature of the water?
A) 102 B) 27.6 C) 35.0 D) 142
13) How much heat is required to melt 1.5 moles of NaCl at its melting point (Hfus = 30 kJ/mol) ?A) 1.5 kJ B) 15 kJC) 20 kJD) 30 kJ
14) 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 (Hvap) of this substance?
A) 20 kJ/mol B) 25 kJ/mol C) 475 kJ/mol D) 525 kJ/mol
15) What amount of heat (in kJ) is required to melt 35.0 g of ice at 0oC? A) 3.09 kJ B) 11.7 kJ C) 20.9 kJ D) 79.1 kJ
16) What amount of heat (in kJ) is required to completely convert 190.0 g of liquid water at 18oC to steam at 100.0oC?
A) 6.51 kJB) 6.94 kJC) 430 kJD) 559 kJ
17) Which of the following statements is false? A) Internal energy is a state function. B) Enthalpy is an intensive property. C) The enthalpy change for a reaction is equal in magnitude, but opposite in sign, to the
enthalpy change for the reverse reaction. D) The enthalpy change for a reaction depends on the state of the reactants and
products.
18) The value of H0 for the reaction below is -1107 kJ: 2Ba(s) + O2 (g) 2BaO (s) How many kJ of heat are released when 5.75 g of Ba(s) reacts completely with oxygen to form BaO(s)?
A) 96.3 B) 26.3 C) 46.4 D) 23.2
19) The value of H0 for this reaction is -1107 kJ: 2Ba(s) + O2 (g) 2BaO (s) How many kJ of heat are released when 5.75 g of BaO(s) is produced?
A) 56.9 B) 23.2 C) 20.8 D) 193
20) The value of H0 for the reaction below is -1107 kJ: 2Ba(s) + O2 (g) 2BaO (s) How many kJ of heat are released when 15.75 g of Ba(s) reacts completely with oxygen to form BaO(s)?
A) 20.8 B) 63.5 C) 114 D) 70.3
