Chem Ch. 1-5.1 definitions Flashcards Preview

Chemistry 110 > Chem Ch. 1-5.1 definitions > Flashcards

Flashcards in Chem Ch. 1-5.1 definitions Deck (44):
1

Theory

•Represents the best current explanation for a phenomenon, but it is always tentative.

• organizes scientific knowledge.

2

Scientific law

•Large amounts of scientific data summarized in brief verbal or mathematical statements.

•A summary of experimental and/or observational data, often expressed in the form of a mathematical equation.

3

Hypothesis

An educated guess.

4

Model

•A design used to classify and organize information; a means for understanding nature.

• summarizes some aspects of what is being studied in a simplified fashion.

5

Matter

The stuff that makes up all material things. It is anything that occupies space and has mass.

6

Mass

•A measure of the quantity of matter that an object contains.

•Weight is a measurement of the force of attraction between two masses, usually one large one like Earth or the moon.

7

Variable

Something that can change over the course of an experiment.

8

Molecule

A group of atoms bound together as a single unit.

9

Element

One of the fundamental substances from which all material things are constructed.

Cannot be broken down into simpler substances by any chemical process.

10

Compound

A substance made up of two or more elements chemically combined in a fixed ratio.

11

Chemical symbol

One or two letters derived from the name of the element. Each element can be represented by this.

12

Atom

The smallest characteristic part of an element.

13

Chemophobia

And unreasonable fear of chemicals.

14

Kelvin (K)

K = *C + 273.15

The SI base unit of temperature.

15

Paragigm

Final level of scientific conceptualization-a set of grand or all encompassing theories.

A distinct set of concepts or thought patterns, including theories research methods postulates and standards for what constitutes legitimate contributions to a field.

15

Scientific Fact

Repeated observations that produce the same result every time.

16

Chemical formula

The combination of elemental symbols used to describe a chemical compound. It consists of letters and where applicable subscript numbers.

17

Mixture

Two or more pure substances combined with each other.

The composition of a mixture may vary from one part of the sample to another.

18

Phase

The state that a specific amount of matter is in; it is usually solid, liquid or gas.

A physically distinctive form of matter such as a solid, liquid, gas or plasma.

19

Celsius

Temperature scale used by the international system of units. Based on 0°C as the melting point of water and 100°C as the boiling point. Boiling point varies with altitude.

20

Atomic mass units (amu)

Expressed in Atomic mass units, or just units.

Relative atomic weight based upon carbon-12.

21

Electron

Negatively charged units.

22

Proton

A unit that has a positive charge in the nucleus. Has a charge equal in magnitude to that of the electron.

23

Neutron

A particle with about the same mass as a proton but with no electrical charge.

Neutral charge

24

X-ray

A form of high electromagnetic radiation- energy with electric and magnetic components.

25

Radioactivity

The spontaneous decomposition of unstable atomic nuclei.

26

Nucleus

The positively charged central core of an Adam consisting of protons and neutrons and containing nearly all its mass.

27

Atomic number

Number of protons in the nucleus. The atomic number identifies which element an atom is.

28

Atomic weight

Determined by the statistical technique known as weighed average.

29

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

30

Period

A horizontal row of elements in the periodic table.

31

Group

A vertical column of elements in the periodic table.

32

Noble gases

Non-chemically reactive, colorless gasses composed of single Atoms.

They are non-reactive because they possess an ideal number of electrons.

33

Halogens

Diatomic molecules that readily form negatively charged components of salts.

34

Alkali metals

Soft metals that do not exist in nature as free elements do to their reactivity; readily form positively charged components of salts.

35

Alkaline earth metals

Harder, less reactive, elements than alkali metals; however, they react vigorously with oxygen.

36

Transition metals

The metallic elements that serve as a bridge, or transition, between the two sides of the periodic table.

Can form colored compounds, commonly possesses different oxidation states, many can be magnetic, Have high densities- freezing and boiling points.

37

Fluorescence

The glow given off by certain chemicals when exposed to strong sunlight.

Certain chemicals exhibit florescence after exposure to strong sunlight.

38

Valence electron

Determine most of the chemistry of an atom. The name of that outermost shell of an atom. The group number tells us how many electrons are in the outer most shell.

39

Carbon dating

Relatively accurate, can date back to 60-70,000 YBP. (Years before present)

Can address anything that has carbon in it from less than 70,000 YBP.

40

Electromagnetic spectrum

Light Energy occurs across a continuum of wavelengths.

41

Chemical equation

A notation system used to represent a chemical reaction. It consists of symbols for reaction species and product species separated by arrow (indicating the direction of the reaction).

42

Chemical reaction

When some or all of the chemical bonds in the reactants are broken and new bonds are formed as the products are created.

43

Coefficient

The number in front of the compound or molecule. Tells how many atoms are present.