Chemistry Midterm

Question 1

Dimensional Analysis

Answer 1

Given Unit * (Desired Unit/Given Unit)

Question 2

Precision

Answer 2

how close a series of measurements are to each other

Question 3

Accuracy

Answer 3

how close a value is to an accepted value

Question 4

Graduated Cylinder

Answer 4

used to measure volumes of liquids

Question 5

Sig-Fig Rules

Answer 5

All non- zero numbers are always significant
Captive zeroes (between non zero numbers) are significant
If a decimal point is present, trailing zeros are significant
If a decimal point is not present, trailing zeros are not significant
Leading zeros are not significant

Question 6

Adding and Subtracting Sig Figs

Answer 6

least precise measurement

Question 7

Multiplying and Dividing Sig Figs

Answer 7

Fewest significant figures

Question 8

Elements

Answer 8

cannot be further broken down through chemical means

Question 9

Smallest particle of an element

Answer 9

an Atom

Question 10

Compounds

Answer 10

chemically combined elements

Question 11

Diatomic Elements

Answer 11

can only exist paired or in a compound — HONClBrIF

Question 12

Monatomic Elements

Answer 12

group 18, noble gases

Question 13

homogeneous mixture

Answer 13

uniform throughout

Question 14

heterogenous mixture

Answer 14

is not uniform throughout

Question 15

suspension mixture

Answer 15

heterogenous; particles that don’t dissolve, settle over time, seen through a microscope

Question 16

colloid mixture

Answer 16

heterogeneous; stay suspended throughout the mixture, too small to settle

Question 17

Seperation of Mixtures

Answer 17

Filteration - particle size
Distillation - boiling points
Separatory Funnel
Chromatography

Question 18

Cathode Ray Tubes

Answer 18

Pass electricity through a gas that is contained at a very low pressure

Question 19

Bohr Model

Answer 19

PEL #1 lowest in energy, closest to nucleus
PEL #7 highest in energy, farthest from nucleus
Lower energy levels are preferred by nature

Question 20

Excited State

Answer 20

when electrons absorb energy

Question 21

Ground State

Answer 21

electrons prefer lower energy, so they release energy in amounts called quanta.

Question 22

orbitals

Answer 22

each PEL is divided into up to 4 sublevels: s, p, d, and f. within each sublevel there are orbitals ; regions in which electrons are most likely to be found

Question 23

how do electrons fill orbitals

Answer 23

lowest energy (ground state) to highest energy. no pairs are put together unless necessary. no two electrons can ever be in the same place at the same time

Question 24

hybridization

Answer 24

elements can rearrange their electron configurations

Question 25

ion

Answer 25

an atom once it has gained or lost an electron; cation, anion

Question 26

first ionization energy

Answer 26

energy needed to remove the outermost electron from a neutral atom

Question 27

atomic number

Answer 27

of protons in the nucleus of each atom of an element; identification tag

Question 28

Atomic Mass Unit

Answer 28

Mass of atoms

Question 29

Isotopes

Answer 29

Same element, different mass

Question 30

nucleons

Answer 30

protons and neutrons located in atoms nucleus

Question 31

proton

Answer 31

positive charge, mass of 1 amu

Question 32

neutron

Answer 32

no charge, mass of 1 amu

Question 33

electrons

Answer 33

small, negatively charged subatomic particles in electron cloud, mass of 1/1836 amu

Question 34

mass number

Answer 34

number of protons plus neutrons in nucleus of an atom

Question 35

atomic mass

Answer 35

weighted average of all naturally occurring isotopes of an element

Question 36

vertical columns

Answer 36

groups/families

Question 37

horizontal rows

Answer 37

periods, same valuence electrons, same number of occupied PEL's

Question 38

metals

Answer 38

solid at room temp (except mercury) shiny malleable ductile good conductors of heat/electricity low first ionization energies and low electronegativities lose electrons to form cations

Question 39

transition metals

Answer 39

3-12 hard solids, high melting points form colored compounds can form multiple possible positively charged ions

Question 40

metalloids (semi-metals)

Answer 40

located along staircase semi-conductors partially ionic, partially covalent silicon

Question 41

non-metals

Answer 41

right, not including group 18 gases, molecular or network solids brittle, dull high first ionization energies and electronegativities gain electrons, form negative ions

Question 42

noble gases

Answer 42

group 18 non-reative (inert) bc completely filled outer valence shell dont form compounds unless under extreme temp/pressure

Question 43

allotropes

Answer 43

non-metals that exist in two more forms in the same phase; different physical properties and chemical properties - oxygen gas and ozone gas - graphite, diamond