Definitions
Think about that
Concepts
Math :)
Miscellaneous :P
100
What term refers to the randomness of a substance or system?
100
Which contains more energy: 50g of boiling water at 100*C or 50g of steam at 100*C?
50g of steam at 100*C
100
According to the 2nd law of thermodynamics, the entropy of the universe is ______________.
increasing
100
In a laboratory experiment, 30. J of heat was added to a gas piston assembly as the piston did 75 J of work on its surroundings. Calculate AE for this system.
Q + W
30. J + (-75 J) =
= -45 J
100
Heat flows from a _______ temperature to a ________ temperature.
higher to lower
200
What is the internal energy of a system plus the product of its pressure and volume?
enthalpy
200
Internal energy is a _______ function, so it equals the DIFFERENCE of the ________ value and the ________ value.
state
final
initial
200
The enthalpy of formation for any ELEMENT in its standard state is: ____________.
200
A 15.0 g piece of graphite is heated to 100.0°C and placed in a calorimeter. The graphite releases 815.1 J of heat to reach a final temperature of 23.9°C. What is the specific heat of graphite?
Q = mcAT ---> c=Q/mAT
-815.1 J/ (15.0g)(-76.1*C) =
= .714 J/g x *C
200
Lava turning to a solid, would this most likely increase or decrease in entropy
decrease (solids usually have the least disorder)
300
How is energy commonly defined?
the ability to do work
300
When baking soda (sodium bicarbonate, NaHCO3) reacts with acetic acid (HC2H302) from vinegar to form carbon dioxide and water, the reaction mixture warms slightly. Which one is less, the enthalpy of the products or of the reactants.
the enthalpy of the products
300
At constant pressure, enthalpy change equals ___________.
heat
300
In the presence of some metals, ethylene (C2H4) and hydrogen gas react to form ethane (C2H6) according to the following thermochemical equation:
C2H4(g) + H2(g) --->C2H6(g) AH* =-136,98 kJ
If the molar mass of ethylene is 28.05 g/mol, how much heat is liberated when 100.0 g of ethylene reacts?
-488.3 kJ (released)
300
Standard state:
_____ atm
_____ K
1 atm
298 K
400
What is a calorimeter used for? (by definition)
measuring heat flow during physical process or chemical reactions
400
Is heat absorbed or released when water at 0*C changes to ice at 0*C?
released
400
the heat per unit mass required to vaporize a substance at its normal boiling point is: ________ ____ _____________.
heat of vaporization
400
How much heat is required to convert 20.0 g of ice at -50.0°C to liquid water at 0.0°C?
The specific heat of ice is 2.06 J/(g•°C) and the heat of fusion of water is 334 J/g.
8740 J
400
Chemical and physical changes that release heat are known as _____________ processes.
EXOthermic
500
The _______ law of thermodynamics states that the change in a system's internal energy is the SUM of the ___________ added to the system and the _________ done on the system.
first
heat
work
500
In an experiment to determine the energy provided by a food product, a sample of the food is burned in a pressurized container at constant volume; 100 J of heat are released. Because volume is constant, the system does no work on its surroundings. Is the change in internal energy positive, zero, or negative?
negative
500
the amount of heat required to cause a unit rise in temperature of a unit mass of a substance is _________ ____________.
specific heat
500
Under certain conditions, nitrogen gas and oxygen gas react to form the toxic brown gas nitrogen dioxide: N2 (g) + 2 02(g) → > 2 NO2 (g). For this reaction, AH° = 66.2 kJ and AS° = -121.81 J/K; calculate AG° at standard conditions (298 K and 1 atm) and determine it the reaction is spontaneous, nonspontaneous, or in equilibrium at these conditions.
102.5 kJ; nonspontaneous
500
Chemical and physical changes that absorb heat are known as _____________ processes.
ENDOthermic