Bio- Chapter 2

Question 1

Matter

Answer 1

Anything that occupies space and mass

Question 2

Mass

Answer 2

Is a measure of the amount of material in an object

Question 3

Element

Answer 3

Is a substance that cannot be broken down into other substances by chemical reactions

Question 4

What four elements make up 96% of the human body’s weight?

Answer 4

Oxygen, carbon, hydrogen, and nitrogen.

Question 5

Trace Elements

Answer 5

Are required in only very small amounts, but you cannot live without them.

Question 6

Compounds

Answer 6

Substances that contain two or more elements in a fixed ratio.

Question 7

Atom

Answer 7

The smallest unit of matter that still retains the properties of an element.

Question 8

Protons

Answer 8

Is a subatomic particle with a single unit of positive electrical charge

Question 9

Electron

Answer 9

Is a subatomic particle with a single negative charge

Question 10

Neutron

Answer 10

Is electrically neutral

Question 11

Nucleus

Answer 11

The atoms center core

Question 12

When an atom has an equal number of protons and electrons..

Answer 12

its net electrical charge is zero and so the atom is neutral

Question 13

Atomic Number

Answer 13

All atoms of a particular element have the same unique number of protons.

Question 14

Mass Number

Answer 14

The sum of the number of protons and neutrons.

Question 15

Atomic Mass

Answer 15

listed in the periodic table as the bottom number and it is close to the mass number-the sum of its protons and neutrons-but may differ slightly because it represents an average of all the naturally occurring forms of that element.

Question 16

Isotopes

Answer 16

Have the same numbers of protons and electrons as a standard atom of that element but different numbers of neutrons.

Question 17

How many of the naturally occurring elements are used by your body? Which four are the most abundant in living cells?

Answer 17

25, oxygen, carbon, hydrogen, and nitrogen.

Question 18

By definition, all atoms of carbon have exactly 6____, but the number of _____ varies from one isotope to another.

Answer 18

Protons, neutrons

Question 19

Radioactive Isotope

Answer 19

One in which the nucleus decays spontaneously, shedding particles and energy

Question 20

Only__ are directly involved in chemical reactions.

Answer 20

Electrons

Question 21

Chemical Bonds

Answer 21

These interactions usually result in atoms staying close together, held by attractions.

Question 22

Ions

Answer 22

Atoms or molecules that are electrically charged as a result of gaining or loosing electrons

Question 23

Ionic Bond

Answer 23

The attraction between oppositely charged ions

Question 24

Covalent Bond

Answer 24

When two atoms share one or more pairs of electrons. Covalent bonds are the strongest.

Question 25

Molecule

Answer 25

Covalent bonds hold atoms together in this

Question 26

When lithium ion(+) joins a bromide ion(-) to form lithium bromide, the resulting bond is a___ bond.

Answer 26

ionic

Question 27

Polar Molecule

Answer 27

Is one with an uneven distribution of charge that creates two poles, one positive pole and one negative pole.

Question 28

Hydrogen Bonds

Answer 28

These are the weakest attraction

Question 29

Chemical Reactions

Answer 29

Changes in chemical composition of matter.

Question 30

Reactants and Products

Answer 30

Starting molecules to the end product

Question 31

Cohesion

Answer 31

The tendency of molecules of the same kind to stick together.

Question 32

Evaporative Cooling

Answer 32

When a substance evaporates, the surface of the liquid that remains cools down.

Question 33

Solution

Answer 33

a liquid consisting of a homogeneous mixture of two or more substances.

Question 34

Solvent

Answer 34

Dissolving agent

Question 35

Solute

Answer 35

Any substance that is dissolved

Question 36

Aqueous Solution

Answer 36

When water is the solvent, this is the resulting solution

Question 37

Acid

Answer 37

A chemical compound that releases H+ to a solution

Question 38

pH Scale

Answer 38

A measure of the hydrogen ion concentration in a solution.

Question 39

Base

Answer 39

A compound that accepts H+ and removes them from solution.

Question 40

Why does water not spill over the cup?

Answer 40

Surface tension due to waters cohesion

Question 41

Why does ice float?

Answer 41

Ice is less dense than water because the more stable hydrogen bonds lock the molecules into a spacious crystal.

Question 42

Buffers

Answer 42

Substances that minimize changes in pH by accepting H+ when that ion is excess and donating H+ when it is depleted.