General Chemistry - Chemistry - Chang/Overby, 13e, Thermochemistry
Which would be assigned a negative value in a thermochemical equation?
1.) A heat rock cools at sunset. 2.) A compressed spring is allowed to uncoil.
Which of the following options correctly describe a thermochemical system? Select all that apply.
1.) Any energy released by the system must be absorbed by its surroundings. 2.) The system must be carefully defined for energy measurements to be meaningful. 3.) The total energy change of the universe is always zero.
Which of the following statements correctly describe exothermic and endothermic reactions? Select all that apply.
1.) If the container of a reaction becomes colder during the reaction, the reaction is endothermic 2.) The reactants in an endothermic reaction are lower in energy than the products. 3.) An exothermic reaction is one that releases heat to its surroundings.
Which of the following changes in energy would be assigned a negative value in thermochemical equation? Select all that apply.
A compressed spring is allowed to uncoil. A hot rock cools at sunset.
closed system
Allows the transfer of energy (heat) but not mass.
Which of the following options correctly describe the term "standard state" used in thermodynamics?
An element is in its most stable form at 1 atm is in its standard state. To be in its standard state, a substance must be at a pressure of 1 atm.
open system
Can exchange mass and energy, usually in the form of heat with its surroundings
Radiant energy
Energy (Or solar energy) coming from the sun.
Isolated System
Heat generated by a chemical reaction is measured in a well-insulated container
Thermochemistry
Study of heat change in chemical reactions
Energy
The capacity to do work.
Kinetic energy
The energy produced by a moving object.
Calorimetry
The measurement of heat changes
Thermodynamics
The study of the interconversion between heat and other types of energy.
Heat
The transfer of thermal energy between two bodies that are at different temperatures
(Delta)U indicates a(n) ___ in the internal energy of a system.
change
The first law of thermodynamics states that total amount of ___ in the universe remains constant.
energy
The enthalpy of reaction (Delta-H) is defined as the change in enthalpy for a chemical process. If DH is positive, then the enthalpy of the products is ___ than the enthalpy of the reactants
greater
The transfer of thermal energy from one object or system to another is known as ___ and is represented by the symbol ___.
heat; q
The total change in the internal energy of a system is the sum of the energy transferred as ___ and/or ___.
heat; work
U
internal energy
The energy requires to seperate one mole of a solid ionic compound into gaseous ions is called ___ energy. The value of this energy is ___.
lattice; higher
If heat is transferred from a system to its surroundings, and surroundings do work on the system, the sign of q will be ___, and the sign of w will be ___.
negative; positive
A ___ function is path independent, meaning that only the initial and ___ conditions are needed to measure the net change that occurred.
state; final
If we define a particular chemical reaction being studied as the system, then everything outside of that reaction would be called ___. Together with the system, this makes up the ___.
surroundings; universe
Energy is transferred when an object is moved by force results in ___ being done on that object.
work
The expansion of gas at constant pressure is known as pressure-volume ___.
work