Chemistry - Medconnect Practice Papers

atomic size across periodic table

atomic size gradually decrease from left to right

because within period electrons are added

does shape influence the polarity of the molecule

yes

when does pressure affect rate of reaction

in a reaction of gases

it does not however influence the rate of reaction of solids and liquids

oxidation-reduction (redox)

reaction is a type of chemical reaction that involves a transfer of electrons between two species

electrolysis

A process by which an electric current breaks chemical bonds.

electrochemical series

A list of elements in decreasing order of ease with which they lose electrons.

why won't Copper reach with acids to liberate hydrogen

it is below hydrogen in the electrochemical series

sublimation is the

phase transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase

S + O2

SO2

1 mole reacts with 1 mole

Markovnikov's Rule

hydrogen will add to the least substituted carbon of the double bond

H attaches to least stable

sodium hydroxide and alcohols

do not react hence no salt is produced

naming esters

attached to c=o forms oate end portion

peptides are

polyamides of amino acids not polyesters

acronym to remember reactivity series

please stop calling me a careless zebra instead try learning how copper saves gold

(displacement)

s equilibrium aq

nacl aq solution must be

saturated

saturated chemistry definition

single bonds only

concentrated

HCO3-

this species in water can function as both bronsted acid and bronsted base

HNO3

-is strong oxidising agent

-highly corrosive

-reacts with CaO

-salts are NOT called nitrites BUT ACTUALLY CALLED NITRATES

which hydrogen is most easily abstracted in a radical bromination

the most stable hydrogen

bonded to the carbon that has the most c-c bonds

isobars are atoms that hav

the same mass but different atomic numbers

boiling point is determined

by intermolecular bonds

a product of neutralization of strong acid and strong base

KI

which substance releases hydrogen when it reacts with steam

Al Li CH3OH H2S

Li

most alkali metals +h2o

produce hydrogen expect beryllium

g1 and g2

prefix of the first member in alkene or alkyne

eth

primary amines react with carbonyl compounds

products obtained are called imines

reagent that can be used to distinguish between pentanal and pentanone

Ag2O

Tollens test

reagent carboxylic acid to alkyl halide

reaction of alcohols with Pcl5 or PCl3 yields an alkyl halide RCl

H2O bonding

both polar covalent and hydrogen

Which of the following solutions of equal concentration will have a 2-fold higher osmotic pressure than that of a sucrose solution of the same concentration?

KCl

K2SO4

AlCl3

K3PO4

KCl will have a higher osmotic pressure than sucrose. Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane. It is also defined as the measure of the tendency of a solution to take in water by osmosis

measure of the tendency of a solution to take in water by osmosis

osmotic pressure

if the pH value of a salt solution is 7, most likely this is a solution of

Complete neutralisation of a strong acid and a strong base will form a neutral salt and water. HCl is a strong acid and KOH is a strong base. So when they are reacted together, they form a solution with a pH of 7.

product if benzoic acid nitration

1 c between COOH and N2O

All of the substances listed below are natural polymers except:

proteins nucleic acids polysaccharides and lipids

lipids

max number of covalent bonds formed by nitrogen

( normal, not dative)

3

the aq solution of glycerol and water

the aq solution of glycerol freezes at a lower temperature than that of water

rate law

an expression relating the rate of a reaction to the concentration of the reactants

REACTANTS

under similar conditions which of the following is the best reducing agent :

F Br Cl I

Br

To be a reducing agent you transfer electrons onto something else, ie the halide ion loses electrons. Down the group shielding increases and atomic radius , therefore weaker nuclear attraction. The reducing agent, its reducing something else and is actually being oxidised itself.[if it is the agent of something the thing it is the agent of is the effect of its friend]

metal that doesn't give H2 on treatment with HCl

Zn, Fe, Ag, Ca

Ag

unreactive metal ( Cu Ag Au)

molarity

moles of solute/litres of solution

why is Al(OH)3 a weaker base than LiOH

Al is a group 3 metal

are metals reducing or oxidising agents

metals, as solid materials often are reducing agents

metal ions are the oxidized form and act as oxidizing agents already lost e- relatively low electronegativity

isomer questions remember

cyclo molecules can be formed with alkene molecular formulas

chain isomerism

the same molecular formula, but a different arrangement of carbon atoms in the chain

positional isomerism

the same molecular formula, but the functional group in a different position

functional group isomerism

same molecular formula but different functional group

metamerism isomerism definition

Metamerism is a type of structural isomerism in which different alkyl groups are attached to the same functional group.

C6H5-CO-CH3

acetophenone

simplest aromatic ketone

Monosaccharide fructose is classified as an:

ketohexose

COOH + NaOH aq

carboxylate salt

COO-Na+

*LOOK OUT FOR FG IN COMPLEX MOLECULES

phenol + NaOH aq

phenolate salt

O-Na+

The alkaline hydrolysis of fats and oils produces

glycerol and soap

when triglycerides react with NaOH or Koh they are converted into soap and glycerol

alkaline hydrolysis of esters

saponification

structure of aspirin

benzene ring

COOH at C1

COOCH3 at C2

acetyl group

COCH3

glucose

C6H12O6

fructose

common reducing agetns

H2SO4 conc, KmnO4, K2Cr2O7, MnO2, Cl2, H2O2

common oxidizing agents

H2, Zn, C CO, LiAlH4, NaBH4

are solids included in the rate equations

no

their ability to react depends only on the surface at which particles collide, surface remains constant and erosion takes place after the initial phase of the reaction, so a time in the reaction not relates to the rate law

factors effecting deprotonation

-polarity of H-A bond

-size of atom A

-acid strength also depends in the stability of conjugate base

water solution of which compound has the lowest pH

NaHCO3 H2S HBr HCN

HBr

most acidic

Br larger than S

I2 + 10 HNO3 2 HIO3 + 10 NO2 + 4 H2O iodine is `

a reductant and reduces nitrogen

reductant - loses electrons

Acid + alkali

salt + water

reacts with Na but not with NaOH

an alcohol

Na+ and OH- are mobile in NaOH so unable to react with alcohol

(covalent and ionic)

nitrile

RCN

nitro

NO2-

benzene and NaOH

is impossible

benzene is very stable due to its ring structure and pi bonds and only has C and H ie no groups for NaOH to react with

Methylbenzene + Br2

possible

benzanoic acid + NaOH

possible

benzene + H2

possible

tollens reagent

AgNO3 + NH3

glucose is

aldohexose

aldohexose

a hexose with an aldehyde group on one end.

reagent that can be used to distinguish between pentanal and pentanone

Cu(OH)2

litmus paper test

Acid/ ammonia gas: red

Base: blue

type of bonds in KH

ionic

Henry's law states that

the volume of gas that will dissolve in a solvent is proportional to the solubility of the gas and the gas pressure

not apply to solubility of CO2

Exceptions to Henry's Law

CO2

or very dilute

(NH4)2SO4

ammonia sulfate

litmus colour to red

ammonia damp universal indicator

blue

pH of KCN

11

pH value with lowest conc of H+

14

Na2O and Ca(OH)2

do not react as they are 2 bases

metal oxides and metal hydroxides

are both bases

obtain sulfuric acid

dissolving SO3 in water

[make sure its a 3 not 2]

acid+ metal

salt + hydrogen

[BIPRODUCTS]

elimination reaction

The removal of a molecule from a saturated molecule to make an unsaturated molecule

intramolecular dehydration

addition reaction for alcohol, one reactant

alcohol to alkene

triol

glycerol

glucose has a keto group

false

gulcose dissolves in water

yes it dissolves

phenylamine and acetic acid

will not form a salt

benzene and amino group

amino benzene

acetic acid

CH3COOH

total hydrolysis of cellulose produces

glucose

osmotic pressure

pressure that must be applied to prevent osmotic movement across a selectively permeable membrane

osmotic pressure equation

II=iMRT

i: # of particles in solution

M: molarity

R: gas constant

T: tempt in Kelvins

Dissolution (chemical)

minerals dissolved by water or acids. Ex: halite/calcite, carbonates dissolve faster

characteristics of dissolution

-reversible process

-depends on temperature

-depends on the nature of the solvent and solute

equimolar

Containing moles at a ratio equal to the stoichiometric ratio.