Chem Chpt 6 Test Flashcards
How do you describe the flow of heat?
Heat always flows from an area of higher temperature to an area of lower temperature
Word to define randomness of a substance or system
Entropy
Word to define internal energy of a system plus the product of its pressure and volume
Enthalpy
What happens when water at 0 degrees Celsius changes to ice at 0 degrees Celsius?
Heat is released
What changes are expected to increase entropy?
Entropy increases when (spontaneity is positive)
Entropy decreases when (spontaneity is negative)
Name the device used to measure heat flow during physical processes or chemical reactions?
Calorimeter
Define energy
Energy: the ability to do work
Chemical reactions and physical changes that absorb heat are known as ______________.
Endothermic
The change in a system’s internal energy is the sum of heat added to the system and the work done on the system is the _____________ law of thermodynamics.
First law of thermodynamics
The field of chemistry that deals with energy changes in chemical reactions is chemical __________________.
Chemical thermodynamics
The thermodynamic state of a substance in its normal physical state at 1 atm and 298 K is the substance’s ________________.
Standard state
The SI unit of energy, whether heat or work, is the ________________.
Joule
Chemical reactions and physical changes that release heat are known as _____________ processes.
Exothermic
What is specific heat?
The heat required to raise the temperature of the substance 1 degrees Celsius.
What is standard enthalpy of formation?
For reactions in which one mole of a compound is formed from its elements in their standard states, the enthalpy change is called standard enthalpy of formation
What is heat vaporization?
Liquid changing into a gas
What is heat of condensation?
Gas changing into a liquid
What is heat of reaction?
The total amount of heat liberated or absorbed between the start of a reaction and its end, where all the products are at the original temperature of the reactants
What is heat of crystallization?
Liquid turning into a solid
What is heat of fusion?
A solid turning into a liquid
In a certain experiment the temperature of the reactants is measured as 24.6 degrees celsious. After the experiment the temperature of the products is measured as 17.3 degrees celsious. This reaction is endothermic.
True
At a constant pressure, enthalpy change equals heat.
True
When a cup of water evaporates into water vapor the entropy change of the system is positive.
True
The enthalpy of formation for any element in its standard state is negative.
False
Has an assigned enthalpy of zero
According to the second law of thermodynamics the entropy of the universe is decreasing.
False
Entropy is increasing
An endothermic reaction is characterized by a negative change in enthalpy.
False
Positive change in enthalpy
The type of energy associated with position relative to a force is kinetic energy.
False
Potential energy
Evaluate chemical evolution in light of entropy and chemical spontaneity.
Explain your answer
When talking about thermodynamic concepts, the portion of the universe or sample of matter under study is the __________ and everything else is the ________________.
System
Surroundings
Does 25 g of boiling water at 100 degrees Celsius or 25 g of steam at 100 degrees Celsius have more energy?
The 25g of steam water at 100 degrees Celsius
