Chemistry Ch 1

How closely a measure value agrees with the correct value.

The smallest particle of an element that maintains its chemical identity through all chemical and physical changes.

The number of protons in the nucleus of an atom.

Defined as exactly 4.184 joules. Originally defined as the wmount of heat required to raise the temperature on one gram of water from 14.5 degreesC to 15.5 degrees C.

A change in which one or more new substances are formed.

see properities

A substance composed of two or more elements in fixed proportions. Compounds can be decomposed into their constituent elements.

Mass per unit volume, D=m/V.

A substance that cannot be decomposed into simpler substances by chemical means. 

Describes processes that absorb heat energy.

The capacity to do work or transfer heat.

Describes processes that release heat energy.

A property that depends on the amount of material in a sample. 

A form of energy that flows between two samples of matter because of their difference in temperature.

The amount of heat required to raise the temperature of a body one degree Celsius.

A mixture that does not have uniform composition and properties throughout. 

A mixture that has uniform composition and properties throughout.

A property that is independent of the amount of material in a sample. 

A unit of energy in the SI system. One joule is 1kg*m2/s2, which is also 0.2390 cal. 

Energy that matter possesses by virtue of its motion.

Energy cannot be created or destroyed in a chemical reaction or in a physical change; it may be changed from one form to another. 

No detectable change occurs in the total quantity of matter during a chemical reaction or during a physical change. 

The combined amount of matter and energy in the universe is fixed.

See Law of Definite Proportions

Different samples of any pure compound contain the same elements in the same proportions by mass; also known as the Law of Contant Composition.

A measure of the amount of matter in an object. Mass is usually measured in grams or kilograms.

Anything that has mass and occupies space.

A sample of matter composed of variable amounts of two or more substances, each of which retains its identity and properties.

The smallest particle of an element or compound that can have a stable independent existence. 

A change in which a substance changes from one physical state to another, but no substances with different compositions are formed.

See Properties.

Energy that matter possesses by virtue of its position, condition, or composition.

How closely repeated measurements of the same quantity agree with one another.

Characteristics that describe samples of matter. Chemical properties are exhibited as matter undergoes chemical changes. Physical properties are exhibited by matter with no changes in chemical composition.

A general statement based on the observed behavior of matter, to which no exceptions are known. 

Digits that indicate the precision of measurements--digits of a measured number that have uncertainty only in the last digit.

The ratio of the density of a substance to the density of water at the same temperature. 

The amount of heat required to raise the temperature of one gram of a substance one degree Celsius. 

Any kind of matter all specimens of which have the same chemical composition and physical properties. 

A letter or group of letters that represents (identifies) an element.

A measure of the intensity of heat, that is, the hotness or coldness of a sample or object. 

A factor in which the numerator and denominator are expressed in different units but represent the same or equivalent amounts. Multiplying by a unit factor is the same as multiplying by one. 

A measure of the gravitational attraction of the earth for a body.