List of Terms for Exam 1
Terms in this set (68)
determines the quantity, dimensions, or extent of something, usually in comparison to a specific unit. It consists of 2 parts: a numerical quantity followed by a specific unit.
a definite quantity adopted as a standard of measurement.
a digit that is either reliably known or estimated in a measurement, simply the number of measured digits and refers to the precision of the measurement.
relates to the degree of reproducibility of the measurement.
refers to how close the measurement is to the true value, depends on how carefully the instrument of measurement has been calibrated.
the space that a given quantity of matter occupies. There is an exact relationship between length and volume in the metric system (1 mL = 1 cm3 = 1 cc).
the quantity of matter that a sample contains. Similar to weight except that weight is a measure of the attraction of gravity for a sample. I have the same mass on Earth and on the moon and in orbit, but I would have very different weights in those three environments (I prefer my weight in orbit personally!)
a relationship between two units or quantities expressed in fractional form. You can use conversion factors in the factor-label method to convert measurements in one unit to another.
a measure of the intensity of heat of a substance.
Equation to go from C to K
K = C + 273.15
the study of matter and the changes it undergoes
anything that has mass and occupies space
most basic form of matter that exists under ordinary conditions, cannot be broken down into simpler substances
smallest fundamental particle of an element that has properties of that element
unique substance that is composed of two or more elements that are chemically combined
matter with a defined, fixed composition and properties (elements and compounds fit in this category)
nonuniform containing two or more phases with definite boundaries between the phases (salad dressings).
Portions of each component are large enough to be detected by some means and can be separated.
*Phases have one physical state with uniform properties without distinct boundaries.
*the same throughout and contain only one phase (ethanol and water).
*There is no detectable boundary between components.
*Solutions refer to homogenous mixtures with one liquid phase (usually can be separated by distillation.
*Alloys are homogenous mixtures of metallic elements with one solid phase.
those that can be observed without changing the substance into another substance (odor, color, density)
independent of the amount of sample being measured
dependent on the amount of sample being measured
simply a change in physical state of a substance
Ordered to Less Ordered Physical States of Matter
(melting, fusion), (sublimation), (evaporation, boiling, vaporization)
Less Ordered to More Ordered Physical States of Matter
(deposition), (condensation), (freezing)
Reactions that absorb heat
Reactions that release heat are
Reactions that are slow
Reactions that are quick
transform a substance into another substance (outcome of the chemical reaction so to speak)
ratio of the mass to the volume (usually given as g/mL)
the amount of heat required to raise the temperature of one gram of a substance one degree Celsius (or Kelvin), can be used to identify a pure substance. This term relates the temperature change to the amount of heat. (How fast can you boil water? Does it take long for oil to heat up in a pan?) The units for heat energy are generally given as calories (cal) or joule (J) (1 cal = 4.184 J exactly).
Specific Heat (form.)
c = q / m*(tF-tI)
the capacity or ability to do work.
energy that is available because of position or composition (idling car).
energy resulting from motion (moving car).
There are 3 fundamental forces in nature
gravity, electromagnetism, and the nuclear force.
observed as an attractive force exerted by very massive bodies
pertains to charged objects
operates at the very small distances that occur in the nucleus of an atom but are inconsequential at longer distances
Law of Conservation of Mass
states that matter is neither created nor destroyed in a chemical reaction.
Law of Conservation of Energy
Energy states that energy cannot be created or destroyed but only transferred from one form to another.
a grouping of two or more atoms held together by covalent bonds
two atoms in each case are joined and held together by a force that involves the sharing of electrons
composed of molecules with atoms of two or more different elements
compounds are represented by using the symbols for the elements of which they are composed (Ex/ H2O for water, NaCl for table salt).
*The number of atoms present is represented as a subscript numeral to the right of the element symbol.
*No number indicates the present of one atom.
show the order and arrangement of specific atoms (diagrams for the compound).
*When writing_____formulas, the lines connecting the atoms represent chemical bonds.
Matter is composed of small indivisible particles called atoms.
T or F and Why?
False. Atoms can be broken down.
Atoms of the same element are identical and have the same properties.
T or F and Why?
False. Discovery of isotopes with varying neutrons
Chemical compounds are composed of atoms of different elements combined in small whole-number ratios.
Chemical reactions are merely the rearrangement of atoms into different combinations.
Atoms are composed of a small central core
Atoms of a single element that vary in the number of neutrons
number of protons in the nucleus. Located as a subscript number to the left of the elemental symbol in isotopic notation. (DEFINES THE ELEMENT)
total number of nucleons (protons + neutrons). Located as a superscript number to the left of the elemental symbol in isotopic notation. (DEFINES THE ISOTOPE)
is a better measurement of mass for isotopes because it is determined by comparison to a standard, 12C, which is defined as having a mass of exactly 12 atomic mass units (amu).
obtained from the weighted average of the atomic masses of all isotopes stably present in nature depending on the percentage of each isotope that exists (isotopic mass of the "average atom" for that element).
4 categories of compounds
Alloys, Intermetallics, Ionic Compounds, Molecular Substances
(metal mixtures that form solid solutions) (really is misplaced as being called a compound because they are not pure substances)
form discrete units of specific numbers of nonmetal atoms (S2Cl2 = disulfur dichloride, H2O = water, H2O2 = hydrogen peroxide)
This category also contains nonmetals that exist quite stably as atoms (not compounds), like the noble gases (He, Ne, etc.) and diatomic atoms (Cl2, O2) or polyatomic atoms (S4, P8).
(metal + nonmetal)
Atoms can achieve an electrostatic charge. When they become charged, they become ions. Electrostatic forces exist between charges, in which opposite charges attract and like charges repel one another.
ions with a negative charge
ions with a positive charge
atoms with an electrostatic charge (not neutral)
electrostatic forces holding ions together by attraction between + and - charges (strong bond)
Formula Unit or Chemical Formula
simplest whole-number ratio of ions in an ionic compound
Ex: Na+ and Cl- form NaCl, Ca2+ and Cl- form CaCl2, Al3+ and N3- form AlN
groups of atoms that are covalently bonded to each other may also be electrostatically charged.