Chemistry

Question 1

Significant Figures

Answer 1

A way of showing how many digits to include in an answer. to find out the number of sig figs, start at the first nonzero number, and count until the end

Question 2

Dimensional Analysis

Answer 2

A method of using one or more conversion factors to convert an item of one unit into that same amount of another unit.

Question 3

Mass Number

Answer 3

The number of protons and neutrons in an atom

Question 4

Atomic Number

Answer 4

The number of protons in an atom

Question 5

Molar Mass

Answer 5

The mass of an element or compound in grams that would be in 1 mole of that element or compound

Question 6

Mole

Answer 6

A mole is an easier way to count atoms by using Avogadro’s Number (1 mole = 6.022 * 10^23 atoms/units)

Question 7

atom

Answer 7

smallest particle of an element that retains the chemical characteristics of that element

Question 8

element

Answer 8

substance that cannot be separated into simpler substances by a chemical process

Question 9

compound

Answer 9

substance composed of characteristic proportions of two or more elements chemically bonded together and can be separated by chemical processes into component elements

Question 10

mixture

Answer 10

differs from a compound by the fact that a mixture can be separated into its components by physical and chemical methods (ex: salt and water are both compounds, but saltwater is a mixture)

Question 11

homogeneous mixture/solution

Answer 11

all the components are uniformly distributed and the appearance is consistent throughout the sample

Question 12

heterogeneous mixture

Answer 12

mixture where the composition is not uniform and the appearance may be inconsistent

Question 13

intensive properties

Answer 13

independent of the amount of substance present (color, odor, malleability, density, temp etc)

Question 14

extensive properties

Answer 14

dependent upon amount of substance (mass, volumes)

Question 15

physical properties

Answer 15

properties that can be measured or observed without changing the substance (melting point, temperature, density)

Question 16

chemical properties

Answer 16

property that describes how much a substance will react; the substance will change into a new substance from this property (oxidation, flammability)

Question 17

law of definite proportions

Answer 17

principle that compounds always contain the same proportion of their component elements. An equivalent law is the law of constant composition that no matter the source of a compound, it will have the same elemental composition.

Question 18

nucleus

Answer 18

positively charged center of the atom containing nearly all of the mass of an atom. consists of protons and neutrons

Question 19

proton

Answer 19

positively charged subatomic particle

Question 20

neutron

Answer 20

electronically neutral subatomic particle

Question 21

electron

Answer 21

negatively charged subatomic particle

Question 22

isotope

Answer 22

atoms of an element containing the same # of protons but different number of nuetrons

Question 23

cathode ray experiment

Answer 23

identified a negatively charged particle that was emitted from an electrode in a cathode ray tube, an evacuated glass tube with the cathode connected to the negative terminal of a power supply.
The particles consistently deflected under the influence of electric or magnetic fields, indicating that the particle was negatively charged.

Question 24

Rutherford Experiment (gold foil)

Answer 24

Rutherford attempted to validate the plum-pudding model by bombarding a gold foil target with alpha particles from a radioactive source.
The trajectory of the particles could be determined by observing phosphorescent images created by the collision of particles with a phosphorescent screen around the target.

Question 25

precision

Answer 25

how repeatable a measurement is

Question 26

accuracy

Answer 26

how close the measurement is to the true value

Question 27

law of conservation of energy

Answer 27

states that energy cannot be created or destroyed, but it can be converted from one form to another

Question 28

cation

Answer 28

A positively charged ion

Question 29

Anion

Answer 29

A negatively charged ion

Question 30

wavelength

Answer 30

the distance from crest to crest on a wave (m)

Question 31

frequency

Answer 31

number of crests of a wave that pass a stationary point of reference per second (1 Hz = 1 s-1)

Question 32

ground state

Answer 32

when an electron is in the lowest energy level

Question 33

excited state

Answer 33

A state in which an atom has a higher potential energy than it has in its ground state

Question 34

orbital

Answer 34

the space within an atom where the probability of finding an electron is very high

Question 35

principal quantum number

Answer 35

(n) a positive integer that indicates the relative size and energy of an orbital in an atom

Question 36

angular momentum quantum number

Answer 36

(ℓ) an integer with a value ranging from 0 to (n-1) and describes the shape of the orbital

Question 37

magnetic quantum number

Answer 37

(mℓ) has values from -ℓ to ℓ, including zero; tells orientation of the orbital relative to other orbitals

Question 38

spin quantum number

Answer 38

(ms) can only be 1/2 or -1/2 and describes the direction that an electron is spinning

Question 39

Aufbau Principle

Answer 39

An electron occupies the lowest-energy orbital available

Question 40

valence electrons

Answer 40

the outer most electrons, the electrons involved in bond formation

Question 41

Hund’s Rule

Answer 41

orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin