Chemistry Chapter 1 & 2

Microscopic:

objects that can be seen only under magnification.

hypothesis.

Propose a reason, explanation, or educated guess for the observation

Medicine/Biotechnology

Chemistry (biochemists) supplies the medicines, materials, and technology that doctors use to treat their patients.

Experiment

(procedure used to test a hypothesis) or test repeatedly and generate data to support or refute your hypothesis by a controlled experiment (test one variable at a time) for the same result.

Materials

Chemists design and make new materials with improved properties to fit specific needs. Steel, plastics, polymers, microelectronics, and optical fibers are just a few. Plastics, in particular, are now designed and made with conservation of the environment in mind.

Agriculture

Chemists help to develop more productive crops and safer, more effective ways to protect crops.

Environment

Chemists help to identify pollutants (material found in air, water, or soil that is harmful to humans or other organisms) and prevent pollution

Energy

Chemists play an essential role in finding ways to conserve, produce and store energy. The demand for energy will increase with increased population and industrialization.

period

Each horizontal row of the periodic table

group

Each vertical column of the periodic table

Extensive Property

Physical property that is dependent on the amount of matter in a sample. Mass, weight, length, and volume are examples.

Intensive Property

Physical property that is dependent on the type of matter in a sample, not the amount of matter. Color, odor, hardness, solubility, temperature, density, and melting and boiling points are examples.

Mass

The amount of matter than an object has. Weight is a force, mass is not. (w=mg)

(dependent variable).

The variable that is observed during the experiment is the responding variable

independent variable).

The variable that you change during an experiment is the manipulated variable

Universe

To study the universe, chemists gather data from afar and analyze matter that is brought back to earth.

Chemical Change:

a change that produces matter (products) with a different composition than the original matter (reactants).

Scientific law

a concise statement that summarizes the results of many observations and experiments. Law describes a phenomenon without attempting to explain it as a theory does. They are often described using mathematical formulas: theory explains why. Both theories and laws are results of many tested experiments.

distillation

a liquid is boiled to produce a vapor that is condensed into a purer liquid, collected in a second flask. Solid or gaseous dissolved components in the original homogeneous mixture are separated. The solids are left behind in the original flask because their boiling points are much higher than the liquid's boiling point.

Physical Property

a quality or condition of a substance that can be observed or measured without changing the substance's composition. Physical properties include color, solubility, odor, hardness, density, temperature, melting and boiling points, malleability (hammered into sheets), ductility (drawn into wire), mass, volume, and length.

model

a representation of an object or event that is not easily or impossible to test.

filtration

a solid is separated from a liquid by passage of a heterogeneous mixture through filter paper. The solid can't physically pass through the filter but the liquid can, thus separating the mixture

theory

a well-tested explanation for a broad set of observations of why experiments give certain results. A theory is never proven or unreliable because there is always a possibility that a new experiment may give a new result in the future, and thus change the theory.

Chemical Property:

ability of a substance to undergo a specific chemical change. The substance undergoes a chemical reaction to form a new substance with a new composition. Chemical properties can be used to identify a substance. Example: iron plus sulfur yields iron sulfide. Examples of chemical properties include combustibility, corrosion, and reactivity.

Matter

anything that has mass (particles within a space) and volume (occupies space). Matter can come in three common phases: solid, liquid, and gas. All matter has a density, mass, & volume.

Matter:

anything that has mass and occupies space; stuff.

Physical Change:

certain properties of a material change, but the composition of the material does not change. Physical change examples include phase changes such as melting, freezing, condensing, and boiling. Boil liquid water and get steam but not its elements, hydrogen and oxygen. Dissolving, breaking, splitting, cracking, grinding, cutting, crushing, bending, and distilling are also physical changes. Physical changes can be classified as reversible or irreversible. Melting is an example of a reversible physical process, but cutting hair is irreversible.

Compound:

consists of a chemical combination of two or more elements in specific compositions or fixed proportions. Compounds can only be broken down into simpler substances by chemical means. In general, properties of compounds are quite different than the elements from which they were made. Chemical formulas are used to represent compounds. Subscripts in chemical formulas are used to indicate the relative proportions of the elements in the compound. Because a compound has a fixed composition, the formula for a compound is always the same.

Liquid

form of matter that flows, has fixed volume, and takes the shape of its container. Liquids are almost incompressible, but they tend to expand slightly when heated. The particles are in close contact with one another, but the arrangement of particles in a liquid is not rigid or orderly as in a solid. A liquid can flow; it can take the shape of the container in which it is placed or has indefinite shape. The amount of space or volume occupied by the liquid does not change as the shapes of the containers are changed. The volume of a liquid is fixed or constant.

Solid

form of matter that has a definite shape and volume. The shape doesn't depend on its container. The particles are packed tightly, often in an orderly arrangement. Therefore, solids are almost incompressible (difficult to squeeze into a smaller volume). In addition, they expand only slightly when heated.

Gas

form of matter that takes both the shape and volume of its container. Like liquids, gases flow to take the shape of the container that holds them. The particles in a gas are spaced far apart. Unlike liquids, gases expand without limit to fill any space. Because of the space between particles, gases are easily compressed into a smaller volume. Vapor describes the gaseous state of a substance that is generally a liquid or solid at room temperature. An example is steam or water vapor.

periodic table

is an arrangement of elements in which the elements are separated into groups based on a set of repeating properties.

Applied chemistry

is research that is directed toward a practical goal or application. Pure research can lead directly to an application (i.e., Nylon, Sticky Notes), but an application can exist before research is done to explain how it works (i.e., Aspirin). Sometimes, scientists accidentally stumble upon a discovery that they didn't expect to find (i.e., Teflon, Saccharin, Vulcanized Rubber).

Pure chemistry

is the pursuit of chemical knowledge for its own sake. There is no expectation of any practical usage immediately for this knowledge. Most chemists do research that is designed to answer a specific question.

Element:

is the simplest form of matter that makes up the universe and has a unique set of properties which cannot be broken down into simpler substances by chemical means. They are the building blocks for all other substances. It consists of protons, neutrons, and electrons in a specific combination called an atom. There are only 118 known elements. One- or two-letter chemical symbols, developed by Berzelius, are used to represent each element. Most elements are derived from Latin, Greek, and English names. The first letter is capitalized, where the second letter, if it has one, is lower cased. The symbols provide a shorthand way to write chemical formulas for compounds.

Macroscopic:

large enough to see with the unaided eye.

Pure Substance

matter that has a uniform and definite composition. Substances contain only one type of matter. Every sample of a given substance has identical intensive properties because every sample has the same composition. It is an element or a compound.

Mixture

matter which consists of a physical blend of two or more components. Most samples of matter are mixtures. Mixtures may be classified as heterogeneous or homogeneous based on the distribution of their components.

Volume

measure of the space occupied by an object.

Heterogeneous Mixture:

mixture in which the composition is not uniform throughout or evenly distributed; therefore, it is variable. It usually involves two or more distinct phases (a part of the sample with its own uniform composition and properties). Examples include soil, granite, rocky road ice cream, chunky soup, and foam.

Homogeneous Mixture:

mixture in which the composition is uniform throughout; consisting of a single phase. Phase is used to describe any part of the sample with uniform composition and properties. Solution is an alternate name for homogeneous mixture. Solutions may be gas, solid, or liquid. Examples include soda, air, salt water, metal alloys, and water/vinegar.

1.) Organic

study of all substances containing carbon

2.) Inorganic

study of substances other than carbon; essentially nonliving things

5.) Physical

study of the behavior of substances in dealing with the mechanisms, rate, and energy transfer that occur when matter undergoes a change.

3.) Biochemistry

study of the chemical processes within living organisms

4.) Analytical

study of the composition and quantity of substances

law of conservation of mass

that any physical or chemical change must conserve mass. Mass is neither created nor destroyed. This is more easily observed in a closed container.

Technology

the means by which a society provides its members with those things needed or desired. It allows functions to be completed more quickly with less effort.

Chemistry:

the study of composition of matter and the changes that matter undergoes. Because living and nonliving things are made of matter, chemistry affects all aspects of life and most natural events.