Chemistry

Question 1

What 3 forms does matter exist in

Answer 1

Solid
Liquid
Gas

Question 2

What is an element

Answer 2

Pure substance that can not be chemically broken down

Question 3

What is an atom

Answer 3

The smallest particle of an element that still retains its chemical properties

Question 4

What 12 elements occur in large amounts? Most common elements is humans

Answer 4

Major elements
Oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus

Minor elements
Sulfur, potassium, sodium, chlorine, magnesium, iron

Question 5

Atom structure

Answer 5

Atomic nucleus contains two subatomic particles

1 protons carry positive charge +
2 neutrons uncharged
Electrons negatively charged
Move around the nucleus

Question 6

Atomic number

Answer 6

Number of protons unique to each atom

Question 7

Mass number

Answer 7

Number of protons and neutrons

Question 8

Isotope

Answer 8

Number of protons does not equal number of neutrons

Question 9

Uses of isotopes

Answer 9

PET scan

Positron-emission tomography

Question 10

Chemical compound

Answer 10

Stable association between two or more elements combined in a fixed ratio

Question 11

Electrons

Answer 11

Attracted to the positive nucleus

Moves in orbitals, area around the nucleus

Question 12

Valence

Answer 12

Outermost shell

Question 13

Octet rule

Answer 13

Atoms gain lose or share electrons to fill the outermost she’ll

Question 14

No reactive atoms

Answer 14

Atoms that naturally occur with a full outermost shell Called inert do not undergo reactions
Examples helium, neon, argon

Question 15

Chemical bonds three types

Answer 15

Ionic bond
Covalent bond strongest
Hydrogen bond weakest

Question 16

Ion

Answer 16

Atoms that have lost or gained one or more electrons

Number of protons differs from the number of electrons

Have an electric charge + or -
Common human ions sodium, potassium, chloride

Question 17

Cation

Answer 17

Positively charged ion

Question 18

Anion

Answer 18

Negatively charged ion

Question 19

Electronegativity

Answer 19

Measure of an atoms attractiveness to electrons
- depends on atoms size and number of protons

Creates a positive cation from a negative anion
Opposite charged ions are attracted creating ionic bonds

Question 20

Covalent bonds

Answer 20

Bonds that forms when atoms share electrons

Question 21

Nonpolar covalent bonds

Answer 21

Two identical atoms share electrons equally

Nuclei of the atoms have the same number of protons

Question 22

Polar covalent bonds

Answer 22

Occurs between atoms of different elements

• have different numbers of protons and different electronegativities

Question 23

Hydrogen bonds

Answer 23

Weak attraction between opposite charges on adjacent polar covalent molecules

Example water

Question 24

Functions of water in humans

Answer 24

Transports
Lubricates
Cushions
Excretes wastes

Question 25

Properties of water

Answer 25

Cohesion and adhesion

Question 26

Cohesion

Answer 26

Attraction between two polar water molecules due to hydrogen bonds

Question 27

Adhesion

Answer 27

Attraction between water and another polar molecule

Question 28

Properties of water:solvent

Answer 28

Ions and polar molecules dissolve easily in water (solutes) Called hydrophilic water loving Examples glucose, alcohol, salt

Question 29

Substances that do not dissolve in water

Answer 29

Water repels nonpolar molecules called hydrophobic | Example oil

Question 30

Water ionization

Answer 30

Equal number of ions created so water is neutral

Question 31

pH

Answer 31

Expression of the hydrogen ion concentration of a solution Change in one on the pH scale is a change in 10 of hydrogen ion concentration

Question 32

Acid and base

Answer 32

Substance that increases the concentration of H+ when dissolved in water - pH 0-6.99 acid Substance that combines with H+ when dissolved in water - lowers the H+ concentration - pH 7.01-14

Question 33

Cell pH

Answer 33

Fairly close to 7 Chemical reactions constantly produce acids and bases We consume foods that are acidic and basic How do cells maintain a constant pH

Question 34

Buffer

Answer 34

Substance that can take up or release H+ in a solution as the H+ concentration changes Pair of substance one acid and one basic

Question 35

Bicarbonate buffer

Answer 35

When blood pH rises carbonic acid dissociates to form bicarbonate and H+ When blood pH drops bicarbonate binds H+ to form carbonic acid

Question 36

What are all living things made up of?

Answer 36

Matter Has mass Occupies space