Chem Ch. 2 (Matter)
physical properties
A characteristic of a pure substance that can be observed without changing it into another substance
electromagnetic energy
A form of energy that travels through space as waves
Differentiate between physical and chemical properties of matter. give two examples of each property
A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points. A chemical property describes the ability of a substance to undergo a specific chemical change. Chemical properties include flammability, toxicity, and chemical stability.
element
A pure substance made of only one kind of atom
endothermic
Absorbs heat/energy
Compare and contrast gases and plasmas.
Both gases and plasmas consist of energetic particles that are so far apart that attractive forces between particles are inconsequential. both highly compressible, have no definite volume, and can diffuse to occupy a volume of space. gases consist of intact atoms or molecules, while the particle in plasmas are mostly ions and free electrons. The temperature of plasmas are usually several orders of magnitude higher than that of gases.
chemical properties
Characteristics of a substance that determine how it will react with other substances.
thermal energy
Heat energy; is the sum of the kinetic energies of all particles in the system.
Explain the differences between heterogeneous and homogeneous mixtures.
Heterogeneous mixtures are not mixed all the way, and have a distinguishable separation. Homogenous mixtures are the same all the way throughout, or fully mixed.
Third Law of Thermodynamics
No system can reach absolute zero
chemical subscripts
Numbers written at the lower right of a chemical symbol
physical changes at the particle level
The positions or motions of the particles may change; chemical bonds between particles remain unchanged
Thermodynamics
The study of energy transformations that occur in a collection of matter.
explain the difference between temperature and thermal energy
The thermal energy, or heat, of an object is obtained by adding up the kinetic energy of all the molecules within it. Temperature is the average kinetic energy of the molecules
mixture
a material that can be separated by physical means into two or more substances
absolute zero
a temperature of 0 kelvins; the temp at which there is no longer any molecular or atomic movement
Convert the following temperature from the Kelvin to the Celsius Scales. a. 496 K (temperature of rock at 5.9 km depth) b. 2.726 K (average temperature of deep space) c. 1783 K (melting point of steel) d. 273.16 K (triple point of water)
a. 223 °C b. -270.42 °C c. 1510 °C d. 0.01 °C
Convert the following temperatures from Celsius to Kelvin scales. Express your answers to the nearest hundredth of a degree a. 0.00 °C (freezing point of water) b. 22.22 °C (room temperature) c. 100.00 °C (boiling point of water) d. -218.30 °C (melting point of oxygen)
a. 273.15 K b. 295.37 K c. 373.15 K d. 54.85 K
name the principle type of energy involved in each of the following; a. vibrations from a loudspeaker b. a pot of near boiling water c. a camera flash d. the source of explosion of dynamite e. changes occuring at the center of a star f. a rolling ball
a. acoustic b. potential c. electrical d. thermal e. nuclear f. kinetic
For each of the following elements, give the term that best describes how its atoms exist under "normal" conditions. Be as specific as possible. For example, N2 would be a diatomic element. a. oxygen (O2) b. red phosphorus (P4) c. sulfur (S8) d. helium (He)
a. diatomic element b. polyatomic element c. polyatomic element d. monatomic element
Give the number of each kind of atom in the following formula units or molecules. a. 5NaCl b. Ca(OH)2 c. HC2H3O2 d. 4Li2O
a. five Na, five Cl b. one Ca, two O, two H c. four H, two C, two O d. eight Li, four O
Name the changes of state that are described by the following processes. a. Pond water solidifies on a cold winter day. b. The fragrance of an open perfume bottle is smelled from across the room. c. Water leaves a teakettle that is sitting on a hot stove. d. Frost patterns appear on a cold window pane in winter. e. Water mist collects on the bathroom mirror after a shower. f. You smell the odor of moth balls when you open a clothes box. g. As a candle burns, wax drips down the sides of the candle.
a. freezing b. vaporization c. vaporization d. deposition e. condensation f. sublimation g. melting
second law of thermodynamics
all natural processes tend toward the highest entropy and minimum usable energy
atom
an individual unit of a pure substance (element)
heterogeneous
appears to consist of two materials segregated into distinct regions
Kinetic Molecular Theory
based on the idea that particles of matter are always in motion
Is energy something a system does or something it has?
energy is something a system has. the energy of a system consists of the motion of their individual particles and the motion of the system as a whole.
kinetic energy
energy of motion
mechanical energy
energy posessed by an object that is moving or has the potential to move
depostion
gas to solid
examples of physical change
ice melting, wheat being ground into flour, sugar dissolving
formula units
ionic compounds
law of conservation of mass-energy (first law of thermodynamics)
mass and energy cannot be created or destroyed, only converted from one form to another
what is matter, and where did it come from?
matter is anything that occupies space. it was created out of nothing by God
six most common forms of energy
mechanical, thermal, acoustic, electromagnetic, chemical, and nuclear
examples of chemical change
metal rusting, oil burning, wood rotting, food digesting
Robert Brown
named the nucleus; observed movement in matter (brownian motion)
observable chemical changes
new substances are formed that have different chemical and physical properties
coefficient
number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction
chemical symbol
one or two letters that represent an element
sublimation
solid to gas
potential energy
stored energy
Discuss why temperature is the most important factor in determining the state of a substance.
temperature can change the state of a substance very easily. one of the most important factors
Malleability
the ability of a substance to be hammered or beaten into thin sheets
energy
the ability to do work
density
the amount of mass in a given volume
naturalism
the belief that all observations can be explained on the basis of natural cause-and-effect relationships. leaves no room for the supernatural
entropy
the measure of the dispersal of energy
chemical changes at the particle level
the positions and chemical bonds of the particles change
homegeneous
the same throughout
internal energy
the sum of the kinetic and potential energies of all particles in the system
chemical formulas
way of describing elements and number of atoms that make up one molecule of a compound; uses symbols, subscripts and coefficients
suspension
when a heterogeneous mixture consists of groups of solid particles suspended in a liquid or gaseous phase
Sound (Acoustic) Energy
energy caused by the vibrations of an object
monatomic element
An element that occurs naturally as individual atoms
physical changes
Any change that DOES NOT alter the chemical composition of a substance.
matter
Anything that has mass and takes up space
State three evidences that the particles of substance are in continuous motion.
Diffusion of perfume odors in air, evaporation of steam droplets in air, and Brownian motion in microscopic objects.
chemical energy
Energy stored in chemical bonds
nuclear energy
Energy stored in the nucleus of an atom
condensation
Gas to liquid
molecules
Groups of two or more atoms held together by chemical bonds
Since heat transfers only take place between systems with different temperatures, explain why the third law of thermodynamics is support by our current understanding of matter.
In order to cool a point to absolute zero, the thermal energy in the particles at that point would have to flow to a colder spot, which is impossible, since there is no point colder than absolute zero by definition.
vaporization
Liquid to gas
What is a physical change? Give three examples of physical change.
Physical change is anything that changes a physical property of matter. Some examples are ice melting, sugar dissolving in water, and wood being cut.
What are the two main classes of matter, and what characteristics differentiate them?
Pure substances and mixtures. We can differentiate between the two based on physical and chemical properties of matter.
compounds
Pure substances that consist of two or more elements.
List the known states of matter in order form the most energetic to the least.
Quark-gluon plasma, plasma, gas, liquid, solid, Bose-Einstein condensate.
exothermic
Releases heat/energy
observable physical changes
Shape, state, size
(T or F) Liquids flow only when a force acts on them.
T
T or F, Molecules consisting of two or more elements are the smallest indentifiable particles of nonchrystalline compounds.
T
State the first law of thermodynamics. What does this law imply for the origins of matter and energy?
The First Law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy. It implies that it energy has existed since the beginning of time.
conductivity
The ability of an object to transfer heat or electricity to another object.
Ductility
The ability to be pulled into thin wires
electrical energy
The energy of electric charges
Compare the entropy of a firecracker before it is lighted to its entropy after it explodes. Explain the difference.
The firecracker's entropy after it has burst is greater than before it is lighted. The firecracker has less usable energy and its parts are more disorganized (less ordered) after it explodes.
What specifically does thermodynamics investigate? What invention spurred in its development?
Thermodynamics is the study of the movement and conversion of energy. The steam engine.
chemical changes
changes that alter the composition of matter
ion
charged particle consisting of a single atom or group of atoms bonded together that has a net electrical charge
pure substance
consists of only one type of matter
polytomic elements
elements that naturally bond in three or more atom units
diatomic elements
elements that naturally bond into two atom units