Chemistry fundamentals

Question 1

METRIC units

nano

Answer 1

10-9

Question 2

micro

Answer 2

10-4

Question 3

milli

Answer 3

10-3

Question 4

centi

Answer 4

10-2

Question 5

kilo

Answer 5

103

Question 6

mega

Answer 6

106

Question 7

1000 L =

Answer 7

1M3 (1 METER CUBED)

Question 8

1 L =

Answer 8

1000 cm3

Question 9

angstrom

Answer 9

10-10

Question 10

what is density

Answer 10

mass /volume

usually expressed as kg/m3 but also can be in g/cm3 for the mcat know that the density of water is 1 g/cm3

Question 11

how do we go from g/cm3 to kg/m3

Answer 11

multiply by 1000

Question 12

what is the molecular formula?

Answer 12

it gives the identity and number of atoms in the molecule.

Question 13

what is the empirical formula?

Answer 13

smallest whole numbers, it gives the ratio of atoms

Question 14

common polyatomic atoms that we need to know for the MCAT

Answer 14

ammonium NH4+

Hydronium H30+

Question 15

acetate

Answer 15

CH3C02-

Question 16

BICARBONATE

Answer 16

HCO3-

Question 17

CYANIDE

Answer 17

CN-

Question 18

HYDROXIDE

Answer 18

OH-

Question 19

NITRATE VS NITRITE

Answer 19

NO3-
NO2-
ITE = LESS OXGEN

Question 20

PERCHLORATE

Answer 20

CL04-

Question 21

CARBONATE

Answer 21

CO32-

Question 22

SULFATE VS SULFITE

Answer 22

SO42- , SO32- (ITE= LESS OXYGEN)

Question 23

PHOSPHATE

Answer 23

PO43-

Question 24

THE MOLE

Answer 24

One mole of anything has 6.02 x10^23 entities. 
# moles = mass in grams /molecular weight

Question 25

percent mass composition

Answer 25

a molecules emipirical formula can be used to determine the molecules percent mass composition.
we can also use the info about the percent composition to determine the compounds empirical formula.

Question 26

concentration

Answer 26

molarity expresses the concentration of a solution in terms of moles of solute per volume in litres

Question 27

what is the mole fraction?

Answer 27

fraction of moles of a given substance

- useful when more then 1 solute is present and often used when there are mixed gases

Question 28

law of conservation of mass or matter

Answer 28

number of the atoms on the left side of the equation match the number on the right side.

Question 29

Stoichiometric coefficients

Answer 29

precede each compound ! tell us in what poportion the reactants react and in what proportion are the products formed. tells us the ratios of the number of molecules ( moles) that apply to the combination of reactants and formation of products.

Question 30

balancing equations

Answer 30

start with the most complex species in the reaction

Question 31

what is the limiting reagent ?

Answer 31

the reactant we run out of first, it limits how much product the reaction can make. its not necesasarily the reactant that’s initially present in the smallest amount

Question 32

the limiting reagent is always a ?

Answer 32

reactant

Question 33

what is a catalyst?

Answer 33

substance that increase the rate of the reaction without being consumed.

Question 34

what does the oxidation state or the number tell us?

Answer 34

it tells us about the atoms ownership if its valence electrons changes when it forms a compound

Question 35

ionic compounds

Answer 35

have complete transfer of electrons.

Question 36

what happens to covalent compounds ?

Answer 36

oxidation state of an atom is the charge it would have if the compound were ionic.

Question 37

what are the rules for assigning oxidation?

rem : rule higher in the list will take precedence

Answer 37

1) the oxidation state of any element in its standard state is zero
2) the sum of oxidation states of the atoms in a neutral molecule must always be zero and the sum of the oxidation states of the atoms in an ion must always equal the ions charge
3) group 1 metals have a +1 oxidation state and group 2 metals have a +2 oxidation state.
4) fluorine has a -1 oxidation state
5) hydrogen has a +1 oxidation state when bonded to something more electronegative then carbon , but it has a -1 oxidation state when bonded to an atom less electronegative then carbon and a 0 oxidation state when bonded to carbon
6) oxygen has a -2 oxidation state ( exception: in peroxides H202, Na2o2) oxygen has a -1 state bc rule 3 and 5 are higher priority then rule 6.
7) the rest of the halogens have a -1 oxidation state and the atoms of the oxygen family have a -2 oxidation state

Question 38

FONClBrISCH

Answer 38

lists elements in order from more electronegative (F) to the least electronegative (H).
so bonds from H to anything NOT found in this list will give H a -1 charge

Question 39

transition metals

Answer 39

can have different oxidation states depending on the compound they are in. REM : METAL will never assume a - oxidation state.