Chapter 2: The Chemical Context Of Life

Question 1

Define matter.

Answer 1

Anything that takes up space and has mass

Question 2

Define an element.

Answer 2

A substance that cannot be broken down to other substances by chemical reactions.

Question 3

How many known elements have chemists discovered in nature?

Answer 3

92 elements

Question 4

What is a compound?

Answer 4

A substance consisting of two or more different elements combined in a fixed ratio

Question 5

What is NaCl made up?

Hint: gas, solid, liquid, ie

Answer 5

Sodium is a metal and chlorine is a poisonous gas

Question 6

What is an essential element?

Answer 6

An organism needs these to live a healthy life and reproduce

Question 7

How many essential elements do humans need and how many do plants need?

Answer 7

Humans need 25 and plants need 17

Question 8

What 4 elements make up 96% of living matter?

Answer 8

Oxygen, carbon, hydrogen, and nitrogen

Question 9

Define an atom.

Answer 9

Smallest unit of matter that still retains all the properties of the element

Question 10

What are atoms composed of and what at their charges?

Answer 10

Subatomic particles including protons (positive), neutrons (neutral), and electrons (negative)

Question 11

Where are protons and neutrons found at in the atom?

Answer 11

The atomic nucleus

Question 12

How are atoms measured?

Answer 12

With Daltons or atomic mass units

Question 13

How much does one proton/neutron weigh?

Answer 13

1 AMU

Question 14

Define the atomic number.

Answer 14

Number of protons found in the atom that makes it into a specific element.

Question 15

What is the mass number?

Answer 15

Sum of the protons plus neutrons in the nucleus of an atom

Question 16

What is the name for an atom having more or less neutrons?

Answer 16

An isotope

Question 17

Define energy

Answer 17

Capacity to cause change

Question 18

Where are electrons found at?

Answer 18

Electron shells in the cloud

Question 19

True or false?

Electrons have more energy closer to the nucleus.

Answer 19

False

Question 20

What happens when an electron absorbs energy?

Answer 20

It moves to a shell farther away from the nucleus

Question 21

What happens when an electron loses energy?

Answer 21

It falls back to a shell closer to the nucleus and energy is general lost as heat

Question 22

How many electrons can the second electron shell hold?

Answer 22

8

Question 23

What is the outer shell and outer electrons known as?

Answer 23

Valence shell and valence electrons

Question 24

What does inert mean?

Answer 24

Chemically unreactive especially when the valence shell is full

Question 25

What is the three dimensional space where an electron is found 90% of the time?

Answer 25

An orbital

Question 26

Define chemical bonds.

Answer 26

When atoms either share or transfer electrons resulting in the atoms staying close together due to their attraction

Question 27

What is a covalent bond?

Answer 27

Sharing of a pair of valence electrons by two atoms

Question 28

What represents a single bond?

Answer 28

• a single dash

Question 29

What represents a double bond?

Answer 29

= an equal sign

Question 30

What is the atom’s valence?

Answer 30

The number of unpaired valence electrons in an atom

Question 31

What is the attraction of a particular atom for the electrons of a covalent bond?

Answer 31

Electronegativity

Question 32

Differentiate between non polar covalent bond and polar covalent bond.

Answer 32

Non polar covalent bond is when the electrons are shared equally because the two atoms have the same electro negativity. A polar covalent bond is where the electrons are not shared equally due to different electro negativities

Question 33

Define a covalent bond.

Answer 33

Electrons are shared

Question 34

What is the strongest electronegative element?

Answer 34

Oxygen

Question 35

What is an ionic bond?

Answer 35

Two atoms are so unequal in electro negativity that the stronger atom takes the electron from the other atom and causes them to attract to each other due to the different charges

Question 36

What is a positive ion and a negative ion?

Answer 36

Cation is positive and anion is negative

Question 37

What are ionic compounds also known as?

Answer 37

Salts

Question 38

True or false?

Not all salts have equal numbers of cations and anions.

Answer 38

True

Question 39

Define a hydrogen bond.

Answer 39

The partial positive charge of a hydrogen atom and an electronegative atom by a noncovalently

Question 40

True or false?

Not all chemical reactions are reversible.

Answer 40

False

Question 41

What is the vanilla plant used in?

Answer 41

Used in lotions, cosmetics, food products, chocolate, ice cream flavor

Question 42

What is the plant called that we eat the vanilla beans from?

Answer 42

Vanilla planifolia

Question 43

What plant is in the Orchidaeae family and is a vine type orchid and we eat the beans?

Answer 43

Vanilla planifolia

Question 44

How many subatomic particles have been identified?

Answer 44

Over 100

Question 45

How many valence electrons does Na have and how many does Cl have?

Answer 45

Na has 1 and Cl has7

Question 46

What happens in a chemical reaction when bonds are broken?

Answer 46

Basically matter is being reformed into different makeups and no matter is lost and since matter is not lost, we say matter is conserved

Question 47

When bonds are broken, we say that energy is _______.

Answer 47

Consumed

Question 48

Energy is released when bonds are _______.

Answer 48

Formed