Chapter 1 Vocab Flashcards
Chemistry
The scientific study of of matter and its properties, the changes it undergoes, and the energy associated with those changes.
Matter
Anything that possesses mass and occupies volume.
Composition
The types and amounts of simpler substances that make up a sample of matter.
Substance
Matter that has a defined, fixed composition.
State of matter
One of the three physical forms of matter: solid, liquid, or gas.
Solid
One of the three states of matter. A solid has a fixed shape that does not conform to the container of the shape.
Liquid
One of the three states of matter. A liquid fills a container to the extent of its own volume and thus forms a surface.
Gas
One of the three states of matter. A gas fills its container regardless of the shape because its particles are far apart.
Physical property
A characteristic shown by a substance itself, without interacting with or changing into other substances.
Physical change
A change in which the physical form (or state) of a substance, but not its composition, is altered.
Chemical property
A characteristic of a substance that appears as it interacts with, or transforms into, other substances.
Chemical change
(Also a chemical reaction) A change in which one or more substances are converted into one or more substances with different composition and properties.
Energy
The ability to do work.
Potential energy (Ep)
The energy an object has as a result of its position relative to other objects or because of its composition.
Kinetic energy (Ek)
The energy an object has because of its motion.
Scientific method
A process of creative proposals and aimed at objective, verifiable discovers of the causes of natural events.
Observation
A fact obtained with the senses, often with the aid of instruments. Quantitative observations provide data that can be compared.
Data
Pieces of quantitative information obtained by observation.
Natural law
(Also law) A summary, often in mathematical form, of a universal observation.
Hypothesis
A testable proposal made to explain an observation. If inconsistent with experimental results, a hypothesis is revised or discarded.
Experiment
A set of procedural steps that tests a hypothesis.
Variable
A quantity that can have more than a single value.
Controlled experiment
An experiment that measures the effect of one variable at a time by keeping other variables constant.
Model
(Also theory) A simplified conceptual picture based on experiment that explains how a natural phenomenon occurs.
Combustion
The process of burning in air, often with release of heat and light.
SI unit
A unit composed of one or more of the base units of the Système International d’Unités, a revised form of the metric system.
Base unit
(Also fundamental unit) A unit that defines the standard for one of the seven physical quantities in the International System of Units (SI).
Derived unit
Any of the various combinations of the seven SI base units.
Meter (m)
The SI base unit of length. The distance light travels in a vacuum in 1/299,792,458 second.
Volume (V)
The amount of space occupied by a sample of matter.
Cubic meter (m3)
The derives SI unit of volume.
Liter (L)
A non-SI unit of volume equivalent to 1 cubic decimeter (0.001 m3)
Milliliter (mL)
A volume (0.001 L) equivalent to 1 cm3.
Mass
The quantity of matter an object contains. Balances are designed to measure mass.
Kilogram (kg)
The SI base unit of mass.
Weight
The force that is extorted by a gravitational field on an object and is directly proportional to the object’s mass.
Second (s)
The SI base unit of time.
Conversion factor
A ratio of equivalent quantities that is equal to 1 and used to express a quantity in different units.
Dimensional analysis
(Also factor-label method) A calculation method in which arithmetic steps are accompanied by cancelling units that represent physical dimensions.
Density (d)
An intensive physical property of a substance at a given temperature and pressure, defined as the ratio of the mass of the volume: d = m/V.
Temperature (T)
A measure of how hot or cold a substance is relative to another substance. A measure of the average kinetic energy of the particles in a sample.
Heat
(Also thermal energy) The energy transferred between objects because of a difference in their temperatures only.
Thermometer
A device for measuring temperature that contains a fluid that expands or contracts within a graduated tube.
Kelvin (K)
The SI base unit of temperature. The kelvin is the same size as the Celsius degree.
Celsius scale
(Formerly centigrade scale) A temperature scale in which the freezing and boiling points of water are defined as 0°C and 100°C, respectively.
Kelvin scale
The preferred temperature scale in scientific work, which has an absolute zero (0 K, or -273.15°C) as the lowest temperature.
Extensive property
A property, such as mass, that depends on the quantity of substance present.
Intensive property
A property, such as density, that does not depend on the quantity of substance present.
Uncertainty
A characteristic of every measurement that results from the inexactness of the measuring device and the need to estimate when taking a reading.
Significant figures
The digits obtained in a measurement. The greater the number of significant figures, the greater the certainty of the measurement.
Round off
The process of removing digits based on a series of rules to obtain an answer with the proper number of significant figures (or decimal places).
Exact number
A quantity, usually obtained by counting or based on a unit definition, that has no uncertainty associated with it and, therefore, contains as many significant figures as a calculation requires.
Precision
(Also reproducibility) The closeness of a measurement to other measurements of the same phenomenon in a series of experiments.
Accuracy
The closeness of a measurement to the actual value.
Systematic error
A type of error producing values that are all either higher or lower than the actual value, often caused by faulty equipment or a consistent flaw in technique.
Random error
Error that occurs in all measurements (with its size depending on the measurer’s skill and the instrument’s precision) and results in values both higher and lower than the actual value.
Calibration
The process of correcting for systematic error of a measuring device by comparing it to a known standard.
