CHE 101: Chapter 1

Compound

A substance composed of two or more elements in fixed, definite proportions.

Element

A substance that cannot be broken down into simpler substances.

Two samples of sulfur dioxide are decomposed into their constituent elements. The first sample produces 10.5g S and 10.5g O. If the second sample produces 25.2 g O, how much sulfur did it produce? a. 10.5g b. 21g c. 25.2g d. 40.4g

c. 25.2g

Which substance is pure substance? a. seawater b. orange soda c. nitrogen gas d. air

c. nitrogen gas

Scientific Law

A broadly applicable generalization that summarizes some aspect of the behavior of the natural world. Scientific laws are usually formulated from a series of related observations or measurements.

Physical Change

A change in matter in which it changes it appearance, but not its composition.

Chemical Change

A change in which a sample of matter changes reaction.

Mixture

A combination of two or more substances in variable proportions.

Experiment

A measurement or observation of nature that aims to validate or invalidate a scientific theory.

Alchemy

A partly empirical, partly magical, and entirely secretive pursuit with two main goals; the transmutation of the ordinary materials into gold; and the discovery of the "elixir of life," a substance that would grant immortality to any who consumed it.

Theory

A tentative model that describes the underling cause of physical behavior. It gives the fundamental reasons for scientific laws and predicts new behavior.

Atomic Theory

A theory formulated by John Dalton that states that matter is ultimately composed of small indestructible particles called atoms.

Neutrons

Nuclear particles with no electrical charge and nearly the same mass as protons.

In a chemical reaction, A and B combine to form AB. A reaction mixture contains 11g of A and 21g of B. After the reaction, A was completely consumed, but 6g of B remained. What is the mass of the AB that formed? a. 11g b. 21g c. 26g d. 32g

c. 26g

Physical Properties

properties that a compound can display without changing its composition.

Chemical Reaction

A change in matter in which a substance changes its composition.

Dalton, John

British scientist who formulated the atomic theory.

Pure Substance

Any substance composed of only one component

Aristotle

Aristotle accepted Empedocles theory, and added a fifth element-the heavenly ether- perfect, eternal, and incorruptible.

Boyle, Robert

British chemist who published [The Skeptical Chymist], a book that criticized Greek ideas concerning a four-element explanation of Matter. Boyle proposed that substance must be tested to determine whether it was an element. If a substance could be broken down into simpler substances, it was not an element.

Rutherford, Ernest

British physicist who studied the internal structure of the atom with his now-famous gold foil experiment. Based on this experiment, Rutherford formulated the theory of the nuclear atom.

Law of Conservations of Mass

Created by Antoine Lavoisier: Matter is neither created nor destroyed in a chemical reaction.

Law of Constant Composition

Created by Joseph Proust: All samples of given compound have the same proportions of their constituent elements.

Proust, Joseph

French chemist who established the law of constant compositions.

Plato

Greek philosopher who asserted that reason alone was the superior way to understand the natural world.

Empedocles

Greek philosopher who suggested that all matter was composed of four basic materials or elements; air, water, fire, and earth.

Democritus

Greek philosopher who theorized that matter was ultimately composed of small, indivisible particles he called "a tomas," or atoms, meaning "not to cut."

Galilei, Galileo

Italian astronomer who confirmed and expanded on Copernicus's ideas about a sun-centered universe. Galileo was chastised by the Roman Catholic Church for his views.

Copernicus, Nicholas

Polish astronomer who claimed the sun to be the center of the universe.

Chemical Properties

Properties if a substance that can only be displayed when the substance changes its composition.

Thales

Reasoned that any substance could be converted into any other substance, so that all substances were in reality one basic material. He believed that one basic material was water.

Atom

The smallest identifiable unit of an element.

Scientific Revolution

The emergence of modern science during the early modern period, when developments in mathematics, physics, astronomy, biology (including human anatomy) and chemistry transformed views of society and nature.

Gas

The state of matter in which particles are not touching and free to move about with relatively little interaction between particles.

Chemistry

The science that investigates the molecular reasons for those processes that are constantly occurring in our macroscopic world.

Molecule

The smallest identifiable unit of a covalent compound.

Protons

The substances that make up much of our structure.

Scientific Method

The way that scientists learn about the natural world. The scientific method consists of observation, law, theory, and experiment.

Vesalius, Andreas

a Flemish anatomist, portrayed human anatomy with unprecedented accuracy.

Lavoisier, Antoine

a French chemist who published a chemical textbook titled "Elementary Treatise on Chemistry". Lavoisier is known as the father of modern chemistry because he was among the first to carefully study chemical reactions.

Observation

a measurement of some aspect of nature. This may only involve one person making visual observations, or it may require a large team of scientists working together with complex and expensive instrumentation.

Heterogeneous Mixture

a mixture containing two or more regions with different compositions.

Homogeneous Mixture

a mixture with the same composition throughout.

Which statement is best categorized as a law? a. In a chemical reaction, matter is neither created nor destroyed. b. Matter is ultimately composed of tiny indestructible particles called atoms. c. When sodium reacts with chlorine, the mass of the sodium chloride that form equals the sum of the masses of the sodium and chlorine that reacted.

a. In a chemical reaction, matter is neither created nor destroyed.

According to the nuclear theory of the atom: a. Most of the volume of the atom is empty space. b. The nucleus composes most of the volume of the atom. c. Atoms are like solid impenetrable spheres. d. None of the above.

a. Most of the volume of the atom is empty space.

Which state of matter has both fixed volume and a fixed shape? a. solid b. liquid c. gas d. none of the above

a. solid

Which change is a chemical change? a. pulverizing iron to create iron powder b. the rusting of iron c. melting iron d. evaporation of molten iron

b. the rusting of iron

Which description best describes the field of chemistry? a. the science that studies harmful substances b. the science that investigates the connection between the macroscopic world and the particles (atoms and molecules) that compose it c. the science that analyzes the composition of drugs d. the science that investigates how to turn ordinary metals into gold

b. the science that investigates the connection between the macroscopic world and the particles (atoms and molecules) that compose it

Which statement best describes one of the main goals of alchemy? a. to synthesize new substances for household use b. to make the elixir of life, a potion that would grant immortality c. to determine whether matter is composed of atoms d. to determine how bodies move through space

b. to make the elixir of life, a potion that would grant immortality

Which Greek thinker was among the first to suggest that matter was composed of atoms? a. Plato b. Aristotle c. Empedocles d. Democritus

d. Democritus

Which statement is not part of Dalton's atomic theory? a. All matter is composed of indivisible particles called atoms. b. All atoms are alike in mass and other properties. c. Atoms of different element combine to form compounds in simple whole number ratios. d. atoms have an equal number of protons and neutrons.

d. atoms have an equal number of protons and neutrons.

Which substance is an element? a. table salt b. water c. sugar d. oxygen

d. oxygen