unit one - matter and the periodic table

Question 1

define matter and what is it comprised of

Answer 1

physical substance in general, as distinct from mind and spirit and that which occupies space; comprised of atoms

Question 2

define element

Answer 2

substance that cannot be broken down into simpler substances by chemical means

Question 3

define compound

Answer 3

pure substance with atoms of two or more elements chemically united in fixed proportions

Question 4

define aqueous

Answer 4

a liquid phase in which the substance is dissolved in water (containing both the substance and water; like a solvent)

Question 5

main difference between mixture and compound

Answer 5

mixtures can be separated into their individual components without changing the identity of the substances; whereas, compounds cannot be separated without changing the substances into their elemental forms

mixtures of elements and compounds can be separated by physical methods; whereas compounds can only be separated into elements by chemical methods (the bonds must break)

Question 6

how is compressibility of gasses affected by temperature and pressure

Answer 6

as pressure on a gas increases the volume of gas decreases as the particles are forced closer together; as pressure decreases the volume of a gas increases, there is more room for the particles to move around

gasses expand when they are heated, they rise when they are heated; the opposite happens when they get cold

Question 7

words used in chemical changes

Answer 7

rusting, combustion, neutralization, tarnishing, decomposition

Question 8

words used for chemical properties

Answer 8

corrosiveness, flammability, acidity, toxicity

Question 9

what are some physical methods of separation: connect the physical property to the technique

Answer 9

solubility (property) and filtration (technique)

boiling point (property) and distillation (technique)

magnetic susceptibility (property) and magnetic force (technique)

polarity/solubility (property) and chromatography (technique)

density (property) and centrifugation and decanting (technique)

volatility (property) and evaporation (technique)

Question 10

what are the phase transitions between states of matter

Answer 10

liquid to gas: evaporation/evaporation

gas to liquid: condensation

gas to solid: deposition

solid to gas: sublimination

solid to liquid: melting

liquid to solid: crystallization/freezing

Question 11

define sublimination, how does it work

Answer 11

a chemical phenomenon where a substance changes directly from a solid to a gas without going through the liquid phase; this process occurs when a substance is heated to a certain temperature

(think of really cold carbon dioxide and a copper coin)

Question 12

what halogen refer too

Answer 12

reactive non-metals

Question 13

define chemistry

Answer 13

the study of matter and how it changes

Question 14

define matter + its fundamental building block (and the def of chemistry w/ this)

Answer 14

anything that occupies space and has mass; the fundamental building block of matter is the atom

chemistry: the study of anything that occupies space and has mass, and how that anything changes

Question 15

why did john dalton chose the word atom / where did it come from

Answer 15

atom comes from the greek word “atomos” meaning indivisible

Question 16

with so much empty space in an atom - why is matter solid?

Answer 16

nothing ever actually touches, its all electrons repelling each other;

so why then do we “feel” texture? becuz texture is a macroscopic property of objects, far larger in scale than the individual atoms

Question 17

what subatomic particle determines the element

Answer 17

how many protons there are - also called the atomic number or nuclear charge (Z)

Question 18

define isotope

Answer 18

elements with the same number of protons but different number of neutrons

Question 19

atomic number (Z) vs. mass number (A)

Answer 19

number of protons (identifies which element)
vs.
the sum of protons and neutrons (helps to identify isotope)

Question 20

define ion: cation vs. anion

Answer 20

an element with a charge other than zero:
cation (+)
anion (-)

Question 21

define average atomic mass

Answer 21

the population weighted avg. for all naturally occurring isotopes of an element

Question 22

how are wavelength and frequency related

Answer 22

inversely proportional - as one goes up the other must go down; speed (c = 3x10^8 m/s = Yv) is a constant

Question 23

wave vs. particle nature and what each dictate

Answer 23

wave dictates color: larger = red/warmer (low energy); smaller = blue/cooler (high energy)
vs.
number of photons dictates intensity: few = dim (low intensity); a lot = bright (high intensity)

Question 24

emission vs. absorption spectroscopy

Answer 24

study of photons released as a molecule relaxes from an excited energy state (energy increases; color becomes cooler)
vs.
study of photons absorbed to create excited energy states (energy decreases; color becomes warmer)

Question 25

define an orbital + define an orbital using quantum numbers

Answer 25

a region with 90% probability of finding an electron principle: n (dictates overall size and energy; as n increases, so does size and energy) angular momentum: l (dictates orbital shape; as l increases, so does shape complexity and energy; cannot be bigger than n-1) magnetic: m [subscript l] (dictates orbital orientation; limited by the value of l, m = -L, ..., 0, ... +L)

Question 26

orbital shapes

Answer 26

l = 0, 1, or 2 0 = s orbital (sphere) 1 = p orbital (peanut) 2 = d orbital (dbl peanut)