A potato shoots out of a cannon, sometimes flying hundreds of feet, and the cannon emits heat to the surroundings. If the burning of the rule performs 855 J of work on the potato and produces 1422 J of heat, what is the change in energy for the burning of
-2277 J
A cylinder and position assembly is warmed by an external flame. The contents of the cylinder expand, doing work on the surroundings by pushing the piston outward against external pressure. If the system absorbs 559 J of heat and does 488 J of work, what
71 J
How much heat is absorbed by a penny as it warms from the temperature of the snow, which is -8.0 C, to the temperature of your body, 37.0 C? Assume the penny is pure copper an has a mass of 3.10 g. The specific heat of copper is 0.385 J/gC
53.7 J
A rock has a mass of 4.7 g and upon absorption of 57.2 J of heat, the temperature of the rock rises from 25 C to 57 C. Find the specific heat capacity of the substance and determine whether the value is consistent with pure gold. (Pure gold has a heat cap
Heat capacity = 0.380 J/gC
This s not consistent with the heat capacity of pure gold
A 3.25 g cube of aluminum initially at 45.8 C is submerged into 105.3 g of water at 15.4 C. What is the final temperature of both substances at thermal equilibrium?
Final temperature = 17.3 C
A block of copper of unknown mass has an initial temperature of 65.4 C. The coper is immersed in a beaker containing 95.7 g of water at 22.7 C. When the two substances reach thermal equilibrium, the final temperature is 24. 2 C. What is the mass of the co
37.8 g Cu
To inflate a balloon you must do pressure-volume work on the surroundings. If you inflate a balloon from a volume of 0.100 L to 1.85 L against an external pressure of 1.00 atm, how much work is done? (in joules)
-177 J
A cylinder equipped with a piston expands against an external pressure of 1.58 atm. If the initial volume is 0.485 L and the final volume is 1.245 L, how much work is done? (in joules)
-122 J
When 1.010 g of sucrose (C12H22O11) undergoes combustion in a bomb calorimeter, the temperature rises from 24.92 C to 28.33 C. Find the change in energy for the combustion of sucrose in kJ/mol sucrose. The heat capacity of the bomb calorimeter is 4.90 kJ/
-5.66 x 10^3 kJ/mol
State whether the following situations are endothermic or exothermic
1. sweat evaporating from the skin
2. water freezing in a freezer
3. wood burning in a fire
1. endothermic, positive change in enthalpy (H) because it absorbs heat
2. exothermic, negative change in enthalpy (H) because the water is releasing heat
3. wood releases heat, so it is exothermic with a negative change in enthalpy (H)
An LP gas tank in a home barbecue contains 13.2 kg of propane, C3H8. Calculate the heat (in kJ) associated with the complete combustion of all the propane in the tank.
C3H8 + 5O2 --> 3CO2 + 4H2O change in H= -2044 kJ
-6.12 x 10^5 kJ
What is the specific heat capacity of a metal if it requires 1178.6 J to change the temperature of 18.7 g f metal from 38.00 C to 64.50 C?
...
Determine the density of NO2 gas at STP.
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A piece of iron (mass = 25.0 g) at 125 C is placed in a styrofoam coffee cup containing 25.0 mL of water at 23 C. Assuming that no heat is lost to the cup or the surroundings, what will the final temperature of the water be? The specific heat capacity of
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A gaseous mixture containing 1.0 mol Ar and 3.5 mol CO2 has a total pressure of 7.5 atm. What is the partial pressure of Ar?
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To what temperature must a balloon, initially at 25 C and 2.00 L, be heated in order to have a volume of 6.00 L?
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Which compound should have the largest lattice energy?
-SrI2
-CaCl2
-NaI
-MgO
-KF
...
Use standard enthalpies given below to determine the change in enthalpy (H) for the following reaction:
2S(s) + 3O2(g) --> 2SO3(g) Hrxn=?
Given:
SO2(g) --> S(s) + O2(g) Hrxn=+296.8 kJ
2SO2(g) + O2(g) --> 2SO3(g) Hrxn=-197.8 kJ
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A large balloon is initially filled to a volume of 25.0 L at 353 K and a pressure of 2575 mmHg. What volume of gas will the balloon contain at 1.35 atm and 253 K?
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What mass of NO2 is contained in a 13.0 L tank at 4.58 atm and 385 K?
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A 43.9 g piece of copper at 135.0 C is plunged into 254 g of water at 39.0 C assuming that no heat is lost to the surroundings, what will the final temperature of the system be?
40.5 C
How much heat energy is required to raise the temperature of 0.298 mole of water from 35.93 C to 79.84 C? The specific heat capacity of water = 4.18 J/gC.
985 J
A 18.3 g piece of aluminum (which has a molar heat capacity of 0.903 J/gC) is heated to 82.4 C and dropped into a calorimeter containing water (specific heat capacity of water is 4.18 J/gC) initially at 22.3 C. The final temperature of the water is 25.8 C
63.1 g
(you should actually get 63.9 g)
Use the enthalpies of formation provided to calculate the change in enthalpy (H) for the following reaction:
SO2Cl2(g) + 2H2O(l) --> 2HCl(g) + H2SO4(l)
SO2Cl2(g) -364 kJ/mol
H2O(l) -286 kJ/mol
HCl(g) -92 kJ/mol
H2SO4(l) -814 kJ/mol
-62 kJ
To what volume will a sample of gas expand if it is heated from 50.0 C and 2.33 L to 500.0 C?
5.58 L
Which of the following samples will have the greatest volume at STP?
-22 g Ne
-22 g He
-22 g O2
-22 g Cl2
-All would have the same volume at STP
22 g He
Use the enthalpy of formations an the enthalpy of the reaction provided to calculate the change in formation for SO3(g)
2SO2(g) + O2(g) --> 2SO3 (g) Hrxn=-198 kJ
Hf of SO2(g) is -297 kJ/mol
-396 kJ/mol
A piece of iron (mass = 25.0 g) at 398 K is placed in a styrofoam coffee cup containing 25.0 mL of water at 298 K. Assuming that no heat is lost to the cup or the surroundings, what will the final temperature of the water be? The specific heat capacity of
308 K
(you actually get 307 K)
A bomb calorimeter has a heat capacity of 2.47 kJ/K. When a 0.111-g sample of ethylene (C2H4) was burned in this calorimeter, the temperature increased by 2.26 K. Calculate the energy of combustion for one mole of ethylene.
-1.41 x 10^3 kJ/mol
How much energy is evolved during the reaction of 51.2 g of Al, according to the reaction below? Assume that there is excess Fe2O3.
Fe2O3(s) + 2Al(s) --> Al2O3(s) + 2Fe(s) Hrxn=-852 kJ
808 kJ
A 4.61 gram sample of a certain diatomic gas occupies a volume of 4.29-L at 1.00 atm and a temperature of 45 C. Identify this gas.
N2
Determine the mass of water formed when 12.5 L NH3 (at 298K and 1.50 atm is reacted with 18.9 L of O2 (at 323 K and 1.1 atm).
4NH3(g) + 5O2(g) --> 4NO(g) + 6H20(g)
20.7 g H2O
A sample of 1.58 g of an unknown gas has a volume of 0.682 L. The sample is kept at 60 C, and exerts a pressure of 1.38 atm. What is the gas?
NO2
The rate of effusion of oxygen to an unknown gas is 0.935. What is the other gas?
N2
When 0.72 g of a liquid is vaporized at 110 C and 0.967 atm, the gas occupies a volume of 0.559 L. What is the molecular mass? Calculate the formula of the gas if the empirical formula of the gas is CH2.
41.68
C3H6