Physical Chemistry Flashcards
(210 cards)
One kilogram of water (c = 4.2 kJ/kgK) is heated by 300 Btu energy. What is the change in temperature in K?
A. 73.8
B. 17.9
C. 74.4
D.75.4
D.75.4
A sample of metal is weighing 400 g is heated to 96.5ºC and then dropped into a calorimeter containing 2000g of water at 20ºC. If the final temperature becomes 21.5ºC, what is the specific heat of the metal in cal/g-ºC?
A. 0.10
B. 0.12
C. 0.14
D. 0.16
A. 0.10
In an experiment determine the specific heat of copper, a piece of copper weighing 50 g is first heated to 100 ºC in steam. It is then immersed into water at 27 ºC. The water in calorimeter weighs 100 g and the inner aluminum cap weighs 50 g. If the final temperature is 30ºC, what is the specific heat of copper, specific heat of aluminum is 0.22 cal/g-ºC?
A. 0.88 cal/g-ºC
B. 0.66 cal/g-ºC
C. 0.077 cal/g-ºC
D. 0.095 cal/g-ºC
D. 0.095 cal/g-ºC
Ten kilograms of -10 C ice is added to 100 kg of 20 C water. What is the eventual temperature, in C, of the water? Assume an insulated container.
A. 9.2
B. 10.5
C. 11.4
D. 12.6
B. 10.5
Two liquids enter a mixing chamber and are discharged at 80ºF at the rate of 50 gal/min. Liquid A enters at 140ºF with specific heat of BTU/gal- ºF. Liquid B enters at 65ºF with specific heat of 8.33 BTU/gal-ºF. What is the volume flow for liquid B?
A. 41.38 gal/min
B. 8.62 gal/min
C. 38.75 gal/min
D. 11.25 gal/min
A. 41.38 gal/min
Suppose you are given of the following hypothetical reactions: X → Y ∆H = -80 kJ ; X → Z ∆H = -125 kJ. Use Hess’s law to calculate the enthalpy change for the reaction Y → Z.
A. -45 kJ
B. +45kJ
C. -205 kJ
D. +205 kJ
A. -45 kJ
From the following heats reaction:
N2 (g) + 2O2(g) → 2NO2(g) ∆H = 67.6 kJ
2NO(g) + O2(g) → 2NO2(g) ∆H = -113.2 kJ
Calculate the heat of the reaction N2(g) + O2(g) → 2NO2(g).
A. 55.6 kJ
B. -55.6 kJ
C. 180.0 kJ
D. -180.8 kJ
C. 180.0 kJ
Aluminum displaces chromium from chromium(III) oxide 2Al + Cr2O3 —- Al2O3 + 2Cr ∆H = -536 kJ. How much heat will be released in the reaction of 10 g of aluminum with 25 g of Cr2O3? Al = 26.98u, Cr= 52u, O=16u
A. -100.6kJ
B. 89.5kJ
C. 58.7kJ
D. -87.9kJ
D. -87.9kJ
The fuel used in spacecraft must contain as much enery per gram of materials as possible. Based on this consideration only, which of the following fuels is best suited to be a spacecraft fuel?
(I) Dimethylhydrazine, (CH3)2NNH2; ∆H of combustion = - 1694 kJ/mol
(II) Methanol, CH3OH; ∆H of combustion = -726 kJ/mol
(III) Ethanol, C2H5OH; ∆H of combustion = -1371 kJ/mol
(IV) Octane, C8H18; ∆H of combustion = -5500 kJ/mol
A. Dimethylhydrazine
B. methanol
C. ethanol
D. octane
D. octane
Consider the following reaction; 2Na(s) + Cl2(g) → 2NaCl (s) ∆H = -821.8 kJ. What is the amount of heat transferred when 5.6 g Na(s) reacts at constant pressure?
A. 821.8 kJ
B. 4600 kJ
C. 2.0 E 2 kJ
D. 1.0 E 2 kJ
D. 1.0 E 2 kJ
C2H6(g) + 3.5 O2 (g) → 2CO2(g) + 3H2O (g) ∆H = -1430 kJ. What is the enthalpy change for the reverse reaction if whole-number coefficients are used?
A. +1430 kJ
B. -1430 kJ
C. -2860 kJ
D. +2860 kJ
D. +2860 kJ
The heat of combustion of a n-heptane at constant volume and 20ºC is 1148.93 kcal/mole. What is the value of the of reaction at constant pressure?
A. -115.13 cal/mole
B. -1151.3 kcal/mole
C. -1151.3 cal/mole
D. 1151.3 kcal/mole
How much oil at 200ºC must be added to 50 grams of the same oil at 20ºC to heat it 70ºC?
A. 12.39 grams
B. 29.12 grams
C. 19.23 grams
D. 23.91 grams
Thirty pounds of ice at 32ºF is placed in 100 lb of water at 100ºF. (The latent heat of ice may be taken as 144 BTU/lb). If no heat lost or added to the mixture, the temperature when equilibrium is reached is
A. 48ºF
B. 49ºF
C. 50ºF
D. 51ºF
D. 51ºF
From the following heats of reaction
2C (graphite) + H2(g) → C2H2(g) ∆H = 227 kJ/mol
6C (graphite) + 3H2 (g) → C6H6 (l) ∆H = 49 kJ/mol
Calculate the heat for the reaction 3C2H2 (g) → C6H6(l)
A. 26.7 kJ/mol
B. -26.7 kJ/mol
C. -178 kJ/mol
D. -632 kJ/mol
D. -632 kJ/mol
From the following heats of reaction;
N2(g) + 2O2(g) → 2NO2(g) ∆H = 67.6 kJ
2NO(g) + O2(g) → 2NO2(g) ∆H = -113.2 kJ
Calculate the heat of the reaction N2(g) + O2(g) → 2NO(g).
A. 55.6 kJ
B. -55.6 kJ
C. 180.0 kJ
D. -180.8 kJ
C. 180.0 kJ
Calculate the standard heat of reaction per mole of C6H6 for the following reaction. C6H6(g) → 3C2H2(g)
A. -650.2 kJ/mol
B. 597.4 kJ/mol
C. 650.2 kJ/mol
D. 750.1 kJ/mol
B. 597.4 kJ/mol
A 220-g sample of quinine, C6H4O2, is burned in a bomb calorimeter whose total heat capacity is 7.854 kJ/ºC. The temperature of calorimeter increases from 23.44ºC to 30.57ºC. What is the heat of combustion per gram of quinine? (molecular weight of quinine is 108.1)
A. -123 kJ/g, -13300 kJ/mol
B. -25.5kJ/g, -2750 kJ/mol
C. -25.5 kJ/kg, -235 kJ/mol
D. -3.57 kJ/g, -385 kJ/mol
B. -25.5kJ/g, -2750 kJ/mol
Calculate the heat of reaction for the following at 25ºC and 1 atm; CaC2 (s) + 2H2O(I) → Ca(OH)2(s) + C2H2(g).
A. -20715 cal
B. -24800 cal
C. -29972 cal
D. -35420
C. -29972 cal
Calculate the equilibrium constant (Kp) for the following reaction at 25ºC: C(graphite) + 2H2(g) → CH4(g).
A. 8.1 E8
B. 1.2 E5
C. 2.8 E6
D. 3.1 E3
A. 8.1 E8
Calculate the change in internal energy for the combustion of 1.00 mol of propene given that change in enthalpy is -2058 kJ.
A. -2052 kJ
B. 2052 kJ
C. 2459 kJ
D. -2450 kJ
A. -2052 kJ
A calorimeter of mass 125 g contains 130 g of water at 20ºC. A 6.1-gram mass of steam at 100 ºC is introduced to calorimeter and condensed in water. What is the final temperature of the water? Assume that no heat is lost to the surroundings and that the value of c for the calorimeter is 0.10 kcal/kg-ºC. Heat of vaporization of water is 540 kcal/kg.
A. 38.5 ºC
B. 42.5 ºC
C. 43.7 ºC
D. 45.5 ºC
D. 45.5 ºC
How many kilograms of ice at 0ºC must be added to 0.6 kg of water at 100 ºC in an insulated 0.1-kg copper container in order to cool the container and its contents to 30ºC? The specific heats of water and copper are 4.2 and 0.39 kJ/kg.K, respectively; the heat of fusion of ice is 335 kJ/kg.
A. 0.39 kg
B. 0.43 kg
C. 0.58 kg
D. 0.61 kg
A. 0.39 kg
The temperatures of three different liquids are maintained at 15ºC, 20ºC, and 25ºC respectively. When equal masses of the first two liquids are mixed, the final temperature is 18ºC, and when equal masses of the last two liquids are mixed, the final temperature is 24ºC. What temperature will be achieved by mixing equal masses of the first and the last liquid?
A. 8.65 ºC
B. 10.30 ºC
C. 15.83 ºC
D. 23.57 ºC
D. 23.57 ºC