Chemistry Semester 1 Final

Chemistry

The study of matter and the changes it undergoes.

Mass

The measure of the amount of matter in an object.

Weight

The force of gravity acting on an object's mass.

Theory

A well-substantiated explanation of some aspect of the natural world that is based on a body of evidence.

Law

A statement that describes an observed phenomenon or pattern in nature without explaining why it occurs.

Density

The ratio of mass to volume for a substance. (D=m/v)

Accuracy

The closeness of a measurement to the true or accepted value.

Precision

The closeness of a set of measurements to each other.

Error

The difference between a measured value and the true or accepted value.

Percent error

The ratio of an error to an accepted value.

Scientific notation

Expresses any number as a number between 1 and 10 (known as a coefficient) multiplied by 10 raised to a power (known as an exponent).

Physical properties/changes

Characteristics of a substance that can be observed or measured without changing the substance's identity.

Intensive physical properties

Properties that do not depend on the amount of substance present.

Extensive physical properties

Properties that depend on the amount of substance present.

Chemical properties/changes

Characteristics of a substance that describe its ability to undergo chemical reactions and form new substances.

Phase changes

Transitions between the different states of matter (solid, liquid, gas).

Law of conservation of mass

The principle that states that mass is neither created nor destroyed in a chemical reaction.

Filtration

A method of separating solid particles from a liquid or gas using a porous barrier.

Distillation

A method of separating a mixture based on differences in boiling points.

Crystallization

A separation technique that produces pure solid particles of a substance from a solution that contains the dissolved substance

Sublimation

The process of a solid directly changing into a gas without passing through the liquid state.

Chromatography

A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of a fixed substrate

Percent by mass

A percentage determined by the ratio of the mass or each element to the total mass of the compound

Radioactivity

The process in which some substances spontaneously emit radiation.

Radiation

The rays and particles that are emitted by radioactive materials.

Nuclear reaction

A reaction that involves changes in the nucleus of an atom.

Radioactive decay

The process by which an unstable nucleus loses energy by emitting radiation.

Alpha radiation

The emission of alpha particles from the nucleus of an atom. Deflects toward a negatively charged plate

Alpha particle

A particle consisting of two protons and two neutrons, equivalent to a helium nucleus. +2 charge.

Beta radiation

The emission of beta particles from the nucleus of an atom. Deflects toward a positively charged plate

Beta particle

A high-speed electron emitted from the nucleus during radioactive decay. -1 charge.

Gamma ray

High-energy radiation that has no electrical charge and no mass. It is not deflected by magnetic or electrical fields, usually accompanies alpha or beta radiation, and accounts for most of the energy lost during radioactive decay.

Isotope

Atoms of the same element that have different numbers of neutrons.

Photon

A particle of light or electromagnetic radiation.

Atomic emission spectrum

The unique set of wavelengths of light emitted by an element when its atoms are excited. Consists of a series of fine lines of individual colors.

Atomic orbital

A three-dimentional region of space around the nucleus of an atom where an electron is likely to be found.

Valence electron

An electron in the outermost energy level of an atom.

Electron-dot structure

A representation of the valence electrons in an atom, using dots to represent the electrons.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Crystal lattice

A three-dimensional geometric arrangement of particles in which each positive ion is surrounded by negative ions and each negative ion is surrounded by positive ions; vary in shape due to sizes and relative numbers of the ions bonded.

Lattice energy

The energy required to separate one mole of an ionic compound into its gaseous ions. Directly related to the size of the ions bonded and is also affected by the charge of the ions.

Formula unit

The simplest ratio of ions in an ionic compound.

Ionic bonds

The electrostatic attraction between oppositely charged ions.

Ionic compounds

Compounds composed of cations and anions held together by ionic bonds.

Metallic bonds

The attraction of a metallic cation for delocalized electrons.

Metallic properties

Properties of metals, such as high electrical and thermal conductivity, malleability, and ductility.

Scientific method

A systematic approach used in scientific investigations to solve problems and answer questions. It involves making observations, forming a hypothesis, conducting experiments, analyzing data, and drawing conclusions.

Qualitative data

Information that describes color, odor, shape or some other physical characteristic.

Quantitative data

Tells how much, how little, how big, how tall, or how fast. (Data represented with a number)

Conclusion

A judgement based on the information obtained.

Dimensional analysis

(Know how to do it)

Experiment

A set of controlled observations that test the hypothesis

Independent variable

The manipulated factor in an experiment that is changed by the researcher.

Dependent variable

The variable in an experiment that is being measured or observed and is expected to change in response to the independent variable.

Hypothesis

A tentative, testable statement or prediction about what has been observed.

Control

The standard for comparison

Electron

Subatomic particle with a negative charge found outside the nucleus of an atom.

Proton

A positively charged subatomic particle found in an atom’s nucleus. It is responsible for the identity of an atom (atomic number).

Neutron

A neutral subatomic particle found in an atom’s nucleus. Its mass is nearly equal to that of a proton.

Period

The rows on the periodic table. Tells the number of electron levels in an atom.

Group

The columns on the periodic table. Tells the number of valance electrons. Elements in the same group have similar properties.

Electron configuration

(Know how to write it)

Calculate wavelength, frequency, and energy of photon

(Know how to do it)

Formulas and names of ionic compounds

(Know how to write them)

Trend of atomic radii

Decreases going to the right, increases going down.

Trend of ionization energy

Increases going to the right, decreases going down.

Trend of electron affinity

Increases going to the right, decreases going down.

Trend of electronegativity

Increases going to the right, decreases going down.

Ionization energy

The amount of energy required to remove an electron from an atom or ion.

Electronegativity

The measure of an atom's ability to attract electrons in a chemical bond.

Electron affinity

The measure of an atom's desire to gain an electron.

Melting

solid to liquid

Freezing

liquid to solid

Ionic Compound

The type of matter that NaCl (Salt) is

Solution/Homogeneous Mixture

The type of matter that mountain dew is

Colloid/Heterogeneous Mixture

The type of matter that milk is

Alloy (Homogenous Mixture)

The type of matter that steel is

Newton

SI Unit for weight

Kilogram

SI Unit for Mass

Deposition

gas to solid