2.1 Bio Content

Question 1

What is matter?

Answer 1

Anything that takes up space and has mass.

Question 2

What is mass?

Answer 2

The amount of matter in an object; it does not vary.

Question 3

What is weight?

Answer 3

The pull of gravity on mass; it varies depending on gravitational strength.

Question 4

What is an element?

Answer 4

A substance that cannot be broken down further by chemical reactions.

Question 5

What is a compound?

Answer 5

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

Question 6

What four elements make up 96% of living matter?

Answer 6

Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N).

Question 7

What is an atom?

Answer 7

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

Question 8

What are the three subatomic particles of an atom?

Answer 8

Protons (+), Neutrons (0), and Electrons (–).

Question 9

Where are protons and neutrons located?

Answer 9

In the nucleus of the atom.

Question 10

Where are electrons found?

Answer 10

In orbitals surrounding the nucleus.

Question 11

What does the atomic number represent?

Answer 11

The number of protons in the nucleus of an atom.

Question 12

What does the mass number represent?

Answer 12

The total number of protons and neutrons.

Question 13

What are isotopes?

Answer 13

Forms of the same element that differ in neutron number and atomic mass.

Question 14

What is the atomic weight of an element?

Answer 14

The average mass of all isotopes based on natural abundance.

Question 15

What is a valence shell?

Answer 15

The outermost electron shell of an atom.

Question 16

What are valence electrons?

Answer 16

Electrons found in the outermost shell that are involved in bonding.

Question 17

When is an atom most stable?

Answer 17

When its valence shell is full.

Question 18

What are covalent bonds?

Answer 18

Bonds formed when atoms share pairs of valence electrons.

Question 19

What is a nonpolar covalent bond?

Answer 19

A bond where electrons are shared equally between atoms.

Question 20

What is a polar covalent bond?

Answer 20

A bond where electrons are shared unequally due to differences in electronegativity.

Question 21

What is electronegativity?

Answer 21

The ability of an atom to attract electrons in a bond.

Question 22

What is an ionic bond?

Answer 22

A bond formed when one atom transfers electrons to another, creating charged ions.

Question 23

What is a cation?

Answer 23

A positively charged ion (lost electrons).

Question 24

What is an anion?

Answer 24

A negatively charged ion (gained electrons).

Question 25

What are hydrogen bonds?

Answer 25

Weak bonds formed when a hydrogen atom is attracted to an electronegative atom in another molecule.

Question 26

What are hydrophobic interactions?

Answer 26

Attractions between nonpolar molecules that cluster together in water.

Question 27

What are van der Waals interactions?

Answer 27

Weak attractions caused by momentary local charge fluctuations.

Question 28

What is potential energy?

Answer 28

Stored energy due to position or structure.

Question 29

What is kinetic energy?

Answer 29

The energy of motion.

Question 30

What is chemical energy?

Answer 30

A form of potential energy stored in chemical bonds.

Question 31

How are covalent bonds related to potential energy?

Answer 31

Longer, weaker bonds have higher potential energy; shorter, stronger bonds have less.

Question 32

What are the shapes of some simple molecules?

Answer 32

CO₂ and N₂ are linear; CH₄ is tetrahedral; H₂O is bent.

Question 33

What determines molecular shape?

Answer 33

The geometry of electron orbitals and repulsion between electron pairs.

Question 34

What is a chemical reaction?

Answer 34

A process where substances (reactants) are transformed into new substances (products).

Question 35

What happens to energy during chemical reactions?

Answer 35

Energy is absorbed to break bonds and released when new bonds form.

Question 36

What is chemical evolution?

Answer 36

The process where simple molecules formed more complex carbon-based molecules, leading to life.

Question 37

What are reactants?

Answer 37

Substances present before a chemical reaction.

Question 38

What are products?

Answer 38

Substances formed as a result of a chemical reaction.

Question 39

What can disturb chemical equilibrium?

Answer 39

Changes in temperature or concentration of reactants/products.

Question 40

What are molecular formulas and structural formulas?

Answer 40

Molecular formulas show the number/type of atoms; structural formulas show how atoms are bonded.