Gen chem 4

Question 1

why dont ionic compounds form true molecules

Answer 1

ionic compounds dnt form true molecules because of the way oppositely charged ions arrange themselves in the solid state

Question 2

what is avogadro number

Answer 2

6.022 x 10^23

Question 3

what is the value for one mole of carbonic acid if its mass is 62 amu?

Answer 3

one mole of the compound has a mass of 62 grams

Question 4

what is the molar mass and what are the units

Answer 4

the molar mass is the mass of one mole of a compound; g/mol

Question 5

how do you find the number of moles of a sample substance

Answer 5

mass of sample(g)/molar mass(g/mol) = moles

Question 6

how do you find the gram equivalent weight and how do you use it to find the number of equivalents?

what is the gram equivalent weight
what is an equivalent(hint: question)

Answer 6

gram equivalent weight= molar mass/n(n is the number of particles of interest produced or consumed in the rxn
equivalents= mass of the compound(g)/gram equivalent weight

gram equivalent weight is the amount of a compound in grams that produces one equivalent of the particle of interest
equivalent: how many moles of the thing that we want(particle of interest) will be produced by one mole of a given substance

Question 7

what is normality, how is it used on the mcat

Answer 7

a measure of conc, given in equivalents per liter

it is used for hydrogen ion concentration

Question 8

what conc of hydrogen ions will a 1 N soln of acid contain?

Answer 8

a 1 N soln of acid will contain a conc of hydrogen ions equal to 1 mol/L

Question 9

in a 1 N soln of HCL, why is the molarity one?

how do normality and molarity relate in an eqn?

Answer 9

M is 1 because HCL is a monoprotic acid

Normality/n=Molarity(n is the number of protons, OH ions, electrons or ions produced or consumed by the solute)

Question 10

how many equivalents of base are needed to neutralize both protons in carbonic acid

Answer 10

2 becuz its diprotic

Question 11

in acid-base chemistry, what two things does the gram equivalent weight represent

Answer 11

the gram equivalent weight represents the mass of acid that yields one mole of protons and there mass of base that yields one mole of OH ions

Question 12

what is percent composition and how is it calc’d?
what other two things can you use to figure it out
what can you also figure out given the perc comp and molar mass of a compound

Answer 12

percent composition of an element (by mass) is the percent of a specific compound that is made up of a certain element
perc. comp of a element in a cmpd is
mass of an element in formula/molar mass x 100= percent comp

you can also use the empirical or molecular formula to figure this out

can figure out the molecular formula

Question 13

what is a: combination reaction, decomposition reaction(and 3 ways it can be caused)
how can you recognize a decomp rxn(what does it have more of?)

Answer 13

combination rxn is when 2 or more reactants form one product
decomp rxn is the opposite of a combination rxn; its wen one product becomes 2 or more products(can be caused by heating, radiation, or electrolysis)\
decomp rxns have more products than reactants

Question 14

what is a combustion rxn

what two products does this rxn make

Answer 14

it involves a fuel(usually a hydrocarbon) and an oxidant(normally oxygen)
it makes Co2 and water

Question 15

what is a single displacement rxn

what is it also called

Answer 15

happens when an atom or ion in a cmpd is replaced by an atom or ion of another element
also known as redox rxn

Question 16

what type of reaction is this?

Cu (s) + AgNO3 (aq) > Ag (s) + CuNO3 (aq)

Answer 16

single displacement rxn

Question 17

what is a double displacement rxn, why does this rxn occur

what is it also called

Answer 17

elements from two different cmpds swap places with each other to make two new compounds
this reaction occurs when one of the products is removed from the soln as a precipitate or gas or when two of the original species combine to form a weak electrolyte that stays undissociated in soln
-metathesis rxn

Question 18

what is a neutralization rxn, what type of rxn is it

Answer 18

an acid reacts with a base to make a salt and usually, water (type of double displacement rxn)

Question 19

how to balance equations (get some steps from youtube

Answer 19

look on youtube

Question 20

3 steps to solvgin stoichiometric coefficients

Answer 20

convert given units to moles, use the mole ratio, convert from moles to the desired units

Question 21

when one reactant is used up or consumed first, what is it called AND why is it called limiting?

Answer 21

the limiting reagent

its called limiting because it limits the amount of product that can be formed in the rxn

Question 22

what are the reactants called that remain after all the limiting reagent is used up

Answer 22

excess reagents

Question 23

what are two things to keep in mind about figuring out the limiting reagent?

Answer 23

• all comparisons of reactants must be done in units of moles, not grams!!!!
• you can just use the absolute mole quantities of the reactants; you need to use the stoichiometric ratios of the reactants combined with the absolute mole quantities to see which reactant is the limiting reagent

Question 24

what is the yield of a reaction(what two yields are there)

Answer 24

the yield can be theoretical(predicted) or actual yield

Question 25

what is theoretical yield(what three things do u have to assume when getting the theoretical yield) how do you find the percent yield

Answer 25

its the max amount of product that can be generated as predicted from the balanced equation, assuming all of the limiting reactant is used up, no side reactions have occurred, and the entire product has been collected actual yield/theoretical yield x 100= percent yield

Question 26

how do you name elements(usually metals) that can form more than one positive ion how do you name monoatomic ions when an element forms two oxyanions,how do you name them?

Answer 26

you name the metal and put the charge in roman numerals in parentheses - monoatomic ions are named by dropping the ending of the name and adding -ide to it(F- is Flouride) - the name of the one with less oxygen ends in -ite, and the one with more oxygen ends in -ate(NO2 Nitrite, NO3 Nitrate)

Question 27

how are extended series' of oxyanions named

Answer 27

``` use the prefixes hypo and hyper(written as per) ClO hypochlorite ClO2 chlorite ClO3 chlorate ClO4 perchlorate ```

Question 28

what do transition metals of MnO4 and CrO4 2- have high what and what happens to reduce it and make them good whats?

Answer 28

they have high oxidation numbers on the metal AND as such they gain electrons in order to bring the oxidation number down to make them good oxidizing agents!!!!!!

Question 29

what kind of ox state do the oxyanions of halogens have

Answer 29

they have a positive ox state

Question 30

why are the solid ionic compounds tend to be poor conductors of electricity

Answer 30

becuz the charged particles are rigidly set in place by the lattice arrangement of the crystalline solid

Question 31

what is the meaning of solvate

Answer 31

to solvate is the tendency of an ionic solute to dissolve

Question 32

what is a strong electrolyte

Answer 32

its strong if it dissociates into its constituent ions

Question 33

three examples the book mention of strong electrolytes

Answer 33

NaCl, KI, and molecular compounds with highly polar covalent bonds that dissociate into ions when dissolved

Question 34

4 exampls the book mentions of weak electrolytes

Answer 34

acetic acid and other weak acids, and ammonia and together weak bases

Question 35

define a nonelectrolyte and examples(3 specific by name)

Answer 35

compounds that dont ionize at all in water, retaining their molecular structure in soon, which may limit their solubility -ex's: many nonpolar gases and organic compounds like O2, CO2 and glucose

Question 36

what compounds are the weakest and why

Answer 36

nonpolar covalent compounds(becuz they dnt form current-carrying ions