Chemistry: Ch 1& 3

Front 1

Atom

Back 1

The smallest unit of an element that still obtains the properties of the element

Front 2

Chemical change

Back 2

When the composition/identity of a substance changes. I.e. rusting, burning (combustion)

Front 3

Chemical property

Back 3

Properties we can only observe or measured by changing the composition or identity of the substance. A chemical change a substance will undergo. Ie: lighting wood on fire

Front 4

Chemical Reaction

Back 4

The process by which one or more substances transform into different substances via a chemical change. Chemical reactions often emit or absorb energy.

Front 5

Compound

Back 5

A substance composed of 2 or more elements in fixed, definite proportions

Front 6

Element

Back 6

A substance that cannot be broken down either physically or chemically. The building blocks of all matter. All elements are organized into the periodic table.

Front 7

Endothermic

Back 7

Absorbs energy from surroundings. I.e. feeling cold, photosynthesis

Front 8

Energy

Back 8

The capacity to do work

Front 9

Exothermic

Back 9

Release/gives off energy to its surroundings. I.e. feels hot (combustion)

Front 10

Gas

Back 10

A state of matter in which atoms or molecules are widely separated and free to move relative to one another

Front 11

Heterogenous mixture

Back 11

A mixture, such as oil and water, that has 2 or more regions with different compositions. Not uniform throught

Front 12

Homogeneous mixture

Back 12

A mixture, such a salt water, that has the same composition throughout

Front 13

Intermolecular forces

Back 13

Attractive forces that exist between molecules

Front 14

Kinetic energy

Back 14

Energy associated with the motion of an object

Front 15

Law of conservation of energy

Back 15

States that energy is neither created nor destroyed. The total amount of energy is constant; energy can be changed from one form to another, or transfered from object to object, but cannot be created out of nothing, and does not vanish into nothing

Front 16

Law of conservation of mass

Back 16

Matter is neither created nor destroyed in a chemical reaction

Front 17

Liquid

Back 17

A state of matter in which atoms or molecules are packed close to each other but are free to move around and by each other

Front 18

Matter

Back 18

Anything that occupies space and has mass. Matter exists in 3 different states: solid (s), liquid (l) and gas (g)

Front 19

Mixture

Back 19

A substance composed of 2 or more different types of atoms or molecules combined in variable proportions

Front 20

Molecule

Back 20

2 or more atoms joined in a specific arrangement by chemical bonds. A molecule is the smallest identifiable unit of a molecular compound.

Front 21

Physical change

Back 21

A change in which matter does not change its composition, even though it's appearance might change

Front 22

Physical property

Back 22

Properties that a substance displays without changing its composition. I.e. H2O is a (s) below 32°F.

Front 23

Potential energy

Back 23

The energy of a body that is associated with its position or the arrangement of its parts

Front 24

Product

Back 24

The final substance produced in a chemical reaction; represented on the right side of a chemical equation

Front 25

Pure substance

Back 25

A substance composed of only one type of atom or molecule

Front 26

Reactant

Back 26

The initial substance in a chemical reaction, represented on the left side of a chemical equation

Front 27

Solid

Back 27

A state of matter in which atoms or molecules are packed close to each other in fixed locations

Front 28

State of matter

Back 28

The three forms in which matter can exist: solid liquid and gas

Front 29

Temperature

Back 29

The temperature of a substance is a measure of its thermal energy. The hotter an object , the greater the random motion of the atoms and molecules that compose it, and the higher its temperature. Not to be confused with heat.

Front 30

Atomic theory

Back 30

A theory stating that all matter is composed of tiny particles called atoms

Front 31

Hypothesis

Back 31

A theory or law before it has become well-established; a tentative explanation for an observation or a scientific problem that can be tested by further investigation

Front 32

Observation

Back 32

Often the first step in the scientific method. An observation must measure or describe something about the physical world

Front 33

Scientific law

Back 33

A statement that summarizes past observations and predicts future ones. Scientific laws are usually formulated from a series of related observations

Front 34

Theory

Back 34

A proposed explanation for observations and laws. A theory presents a model of the way nature works and predicts behavior that extends well beyond the observations and laws from which it was formed

Front 35

Scientific method

Back 35

The way that scientists learn about the natural world involving observations, laws hypotheses, theories and experimentation

Front 36

Steps of the scientific method

Back 36

1. Observation and data collection

2. Hypothesis

3. Design and perform experiment

4. Developed Theory

Front 37

Qualitative properties

Back 37

Does not involve any numbers or measurements during observation. Ie: color, shape, physical state, texture

Front 38

Quantitative properties

Back 38

Does involve numbers or measurements during observation Ie: mass, density, temperature

Front 39

Law

Back 39

Describes how nature operates. Ie the law of gravity

Front 40

How to design an experiment to test a hypothesis

Back 40

1. Only test one variable at a time

2. Has a control group and an experimental group

3. Must run multiple identical trials (a minimum of 3)

Front 41

Variable

Back 41

Any component of an experiment that can experience change

Front 42

Control group

Back 42

Unchanged from the typical condition. The basis for comparison in an experiment