General Chemistry 1

All the big topics and notes for Gen Chem 1

Matter

The physical material of the universe; it is anything that has mass and occupies space.

Property

Any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types.

Elements

A substance that cannot be decomposed into simpler substances.

Atoms

The exceedingly small building blocks of matter.

Molecule

A chemical combination of two or more atoms.

Gas

(also known as vapor) Has no fixed volume or shape; rather, it uniformly fills its container.

Liquid

Has a distinct volume independent of its container, assumes the shape of the portion of the container it occupies, and is not easily compressed.

Solid

Has both a definite shape and a definite volume and is not easily compressed.

Pure substance

(usually referred to simply as a substance) Is matter that has distinct properties and a composition that does not vary from sample to sample.

Compounds

Are substances composed of two or more elements; they contain two or more kinds of atoms.

Mixtures

Are combinations of two or more substances in which each substance retains its chemical identity.

Law of constant composition/ Law of constant composition

A law that states that the elemental composition of a compound is always the same.

Solutions

A mixture of substances that has a uniform composition; a homogeneous mixture.

Heterogeneous

Do not have the same composition, properties, and appearance throughout, vary in texture and appearance in any typical sample.

Physical properties

Can be observed without changing the identity and composition of the substance. These properties include color, odor, density, melting point, boiling point, and hardness.

Chemical properties

Describe the way a substance may change, or react, to form other substances.

Intensive properties

do not depend on the amount of sample being examined and are particularly useful in chemistry because many intensive properties can be used to identify substances.

Extensive properties

such as mass and volume, depend on the amount of sample, relate to the amount of substance present.

Physical change

A substance changes its physical appearance but not its composition: It is the same substance before and after the change.

Chemical change/ Chemical reaction

A substance is transformed into a chemically different substance.

distillation

A process that depends on the different abilities of substances to form gases.

Energy

Defined as the capacity to do work or transfer heat.

Work

is the energy transferred when a force exerted on an object causes a displacement of that object.

Heat

the energy transferred to cause the temperature of an object to increase.

W= F x d

We define work, w, as the product of the force exerted on the object, F, and the distance, d, that it moves.

Force

Is defined as any push or pull exerted on the object

Kinetic energy

The energy of motion.

E_k =1/2 mv²

The magnitude of the kinetic energy, E_k, of an object depends on its mass, m, and velocity, v

Potential energy

The “stored” energy that arises from the attractions and repulsions an object experiences in relation to other objects.

Electrostatic potential energy

Which arises from the interactions between charged particles. Opposite charges attract each other, whereas like charges repel.

SI units

An international agreement was reached specifying a particular choice of metric units for use in scientific measurements

Mass

Is a measure of the amount of material in an object.

Temperature

A measure of the hotness or coldness of an object, is a physical property that determines the direction of heat flow.

Kelvin scale

Is the SI temperature scale, and the SI unit of temperature is the kelvin (K).

Absolute zero

Zero on the Kelvin scale is the temperature at which all thermal motion ceases.

Derived unit

Obtained by multiplication or division of one or more of the base units.

Density

Is defined as the amount of mass in a unit volume of a substance.

Calorie

Was originally defined as the amount of energy required to raise the temperature of 1 g of water from 14.5 to 15.5 °C. It has since been defined in terms of a joule:

Joule

The SI unit for energy, in honor of James Joule (1818–1889), a British scientist who investigated work and heat.

Exact numbers

Those whose values are known exactly

Inexact numbers

Those whose values have some uncertainty

Precision

Is a measure of how closely individual measurements agree with one another.

Accuracy

Refers to how closely individual measurements agree with the correct, or “true,” value.

Significant figures

The digits that indicate the precision with which a measurement is made; all digits of a measured quantity are significant, including the last digit, which is uncertain.

The law of multiple proportions

If two elements A and B combine to form more than one compound, the masses of B that can combine with a given mass of A are in the ratio of small whole numbers.

Electronic charge

1.602×10⁻¹⁹ C.