Bio Test Ch.2 Part1

Front 1

the basic unit of matter is called an

Back 1

atom

Front 2

describe the nucleus of an atom

Back 2

protons and neutrons are located in the nucleus and are binded by a strong force

Front 3

protons have a _______ charge and are located in the ________.

Back 3

positive;nucleus

Front 4

neutrons have a _________ charge and are located in the _________.

Back 4

neutral;nucleus

Front 5

electrons have a __________ charge and are ___________ the nucleus.

Back 5

negative;surround

Front 6

why are atoms neutral despite having charged particles?

Back 6

because atoms have equal numbers of electrons nad protons and because these subatomic particles have = but opposite charges, the atoms are neutral.

Front 7

chemical element

Back 7

pure substance that consists entirely of one type of atom.

Front 8

what does an element's atomic number represent?

Back 8

the number of protons in an atom of an element

Front 9

isotopes

Back 9

atoms of the same element that differ in the number of neutrons they contain.

Front 10

isotopes are identified by

Back 10

their mass number

Front 11

why do all isotopes of an element have the same chemical properties?

Back 11

they have the same number of electrons

Front 12

chemical compound

Back 12

substance formed by the chemical combo of 2 or more elements in definite properties.

Front 13

what holds atoms in compounds together?

Back 13

chemical bonds

Front 14

covalent bond

Back 14

electrons are shared between atoms

Front 15

ionic bond

Back 15

one or more electrons are transferred from one atom to another

Front 16

ion

Back 16

positively charged and negatively charged atom

Front 17

an atom that loses electrons has a ________ charge.

Back 17

positive

Front 18

an atom that gains electrons has a ______ charge.

Back 18

negative

Front 19

the structure that results when atoms are joined by covalent bonds are called _______.

Back 19

molecule

Front 20

the slight attractions that develop between oppositely charged regins of nearby molecules are called _____________.

Back 20

van der waals force

Front 21

in a water molecule each hydrogen forms a _______ covalent bond.

Back 21

single

Front 22

atoms can share 6 electrons and form a _______ bond.

Back 22

triple

Front 23

matter has _______ and ________.

Back 23

mass and volume

Front 24

matter can be _________, ____________, or _________.

Back 24

pure substances, chemical compounds, mixtures

Front 25

matter may exist in three different states:

Back 25

solid, liquid, gas

Front 26

matter may also be ______________ or ____________ mixtures

Back 26

homogenous, heterogeneous

Front 27

are all matters visible? explain.

Back 27

no, some may be odeorless and colorless gases

Front 28

does matter take up space?

Back 28

yes all matter has mass and volume

Front 29

what is matter made of?

Back 29

elemental atoms and chemical compounds

Front 30

atom

Back 30

an entity which cannot be divided furthur and still maintain its unique property

Front 31

atoms are made up of _____________ particles.

Back 31

subatomic

Front 32

how are protons and neutrons bound to the nucleus?

Back 32

by a strong force

Front 33

some isotopes are __________ and _________.

Back 33

unstable, radioactive

Front 34

element

Back 34

substance consisting entirely of one type of atom

Front 35

what does it mean when an isotope is radioactive?

Back 35

their nuclei are unstable and break down at a constant rate over time

Front 36

are radioactive isotopes dangerous?

Back 36

yes it can be dangerous but radioactive isotopes have a number of important scientific and practical uses

Front 37

radioactive isotopes can be used to

Back 37

treat cancer, to kill bacteria that causes food to spoil, and can be used as labels or “tracers” to follow the movements of substances within organisms

Front 38

Because isotopes the same number of electrons..

Back 38

all isotopes of an element have the same chemical properties.

Front 39

a chemical formula indicates the composition of a(an)

Back 39

compound

Front 40

when atoms share four electrons, it forms a _______ bond.

Back 40

double

Front 41

Some atoms have a _______ attraction for electrons than do other atoms.

Back 41

stronger

Front 42

when a covalent bond begins to share electrons, the sharing is _______ equal.

Back 42

not always

Front 43

Even when the sharing of a covalent bond is equal, the rapid movement of electrons can create _______ on a molecule that have a tiny positive or negative charge.

Back 43

regions

Front 44

van der waals force

Back 44

a slight attraction that develops between the oppositely charged regions of nearby molecules

Front 45

a water molecule is _________.

Back 45

neutral

Front 46

what results from the oxygen atom being at one end of a water molecule and the hydrogen atoms being at the other end?

Back 46

oxygen end: slight negative charge
hydrogen end: slight positive charge

Front 47

why is a water molecule polar?

Back 47

because there is an uneven distribution of electrons between the oxygen and hydrogen atoms.

Front 48

_________ bonds are the strongest bonds that form between molecules.

Back 48

hydrogen

Front 49

cohesion attraction

Back 49

an attraction between molecules of the same substance

Front 50

adhesion

Back 50

an attraction between molecules of different substances

Front 51

why is water extremely cohesive

Back 51

because of hydrogen bonding

Front 52

the rise of water in a narrow tube against the force is called

Back 52

a capillary action

Front 53

how does capillary action affect plants?

Back 53

because it draws water out of the root of the plants and up into its stems and leaves

Front 54

what is a mixture?

Back 54

material composed of 2 or more elements or compounds that are physically mixed together but not chemically combined

Front 55

a mixture of two or more substances in which the molecules of the substances are evenly mixed is called a

Back 55

solution

Front 56

the greatest solvent in the world is

Back 56

water

Front 57

what is a suspension?

Back 57

mixture of water and nondissolved materials

Front 58

solute and example

Back 58

substance that is dissolved in solvent to make a solution; tablesalt

Front 59

solvent and example

Back 59

substance in which solute dissolves; water

Front 60

two water molecules react to form

Back 60

ions

Front 61

why is water neutral despite the production of hydrogen ions and hydroxide ions?

Back 61

because the number of positive hydrogen ions produced is equal to the number of negative hydroxide ions produced.

Front 62

what does the pH scale indicate?

Back 62

if something is acidic, basic or neutral

Front 63

what number is neutral on the pH scale?

Back 63

7 (water)

Front 64

the more protons an atom has, the ________ the attraction is for electrons.

Back 64

stronger

Front 65

there is a greater probability of finding shared electrons near an atom with a ________ amount of protons an atom as

Back 65

greater

Front 66

Because of their partial positive and negative charges..

Back 66

polar molecules such as water can attract each other

Front 67

Hydrogen bonds are ______ strong as covalent or ionic bonds

Back 67

not as

Front 68

Water's cohesion causes molecules on the surface of water to be drawn _______, which is why drops of water form beads on a _______ surface

Back 68

inward;smooth

Front 69

Adhesion between water and glass also causes water to rise in a narrow tube against the force of gravity. what is this effect called?

Back 69

a capillary action.

Front 70

Cohesion and adhesion are similar in that

Back 70

both are attractions between molecules.

Front 71

all components of a ________, are evenly distributed.

Back 71

solution

Front 72

Water's ________ gives it the ability to dissolve both ionic compounds and other polar molecule

Back 72

polarity

Front 73

When an ionic compound such as sodium chloride is placed in water, water molecules _______ and ________ the positive and negative ions.

Back 73

surround, separate

Front 74

Some materials do not dissolve when placed in water but separate into pieces so small that they do not settle out. This is called ___________. give an example

Back 74

suspensions; blood

Front 75

the higher the pH the more ________ the solution

Back 75

basic

Front 76

the lower the pH the more _______ the solution

Back 76

acidic

Front 77

base

Back 77

is a compound that produces hydroxide ions (OH− ions) in solution

Front 78

acid

Back 78

is any compound that forms H+ ions in solution.

Front 79

buffers

Back 79

are weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH

Front 80

Controlling pH is important for maintaining __________.

Back 80

homeostasis

Front 81

A molecule in which the charges are unevenly distributed is called a

Back 81

polar molecule

Front 82

A dissolved substance is called a

Back 82

solute

Front 83

A compound that produces hydroxide ions in solution is called a

Back 83

a base