Inorganic 1&2 Flashcards by Martha Robbins

Why phosphorus chloride has this shape and bond angle

Pyramidal
3BP 1LP
Arranged to minimise repulsion
Lone pair-bonding pairs repel more than bond pair-bond pairs

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Why boiling temperature increases from chlorine to iodine

From chlorine to iodine the number of electrons increases

So strength of LDF increases and more energy is required to separate molecules

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Halides+ sulfuric acid

Explain which halide is the strongest reducing agent

Iodide ions are stringers reducing agent because iodide ions reduce sulfur from +6 to 0
bromide ions reduce sulfur from +6 to +4
Chloride ions do not reduce sulfuric acid

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Glowing splint test

Relight a glowing splint

Oxygen gas

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Gases when G2 nitrate is heated and colour

Nitrogen dioxide

Brown

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Why does magnesium carbonate decompose more readily on heating than barium carbonate

Magnisum ion is smaller
Has higher charge density
Which polarises the large carbonate ions and weakens the carbon- oxygen bond

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X2+ ion mass spec.
32, 33, 34, 35, 36
Deduce the formulae of all the species responsible for each peak in mass spec of X2

Oxygen 
32= 16O = 16O+
33 = 16O = 17O+
34 = 16O = 18O+ and 17O = 17O+
35 = 17O = 18O+
36 = 18O = 18O+

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When does magnesium bromide conduct electricity

When molten and dissolved in water

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Silver nitrate solution + excess dilute ammonia solution then added to the precipitate formed
Why did only some precipitate dissolve

The precipitate is a mixture of silver chloride and bromide
Silver chloride dissolves in dilute ammonia
Silver bromide does not dissolve in dilute ammonia

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why is there no reaction between potassium bromide and qaqueous iodine

Iodine is a weaker oxidising agent than chlorine

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Why does calcium nitrate require a higher temperature for decomposition than magnesium nitrate

Ca2+ has larger ionic radius than Mg2+

Ca2+ causes less polarisation of nitrate ion (N-O bonds)

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Observations when magnesium nitrate is heated

Solid dissolves

Brown gas produced

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Explain trend in thermal stability of G2 nitrates

Nitrates increase in stability down G2 as ionic radius increases as you go down group
So polarising ability of metal ion decreases
Wearing of N-O bonds is less

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How this buffer solution helps control the pH of blood when extra CO2 is press due to exercise

CO2 dissolves in blood from carbonic acid = increase conc
Equilibrium shifts to right = produces more H+
High concentration of hydrogen carbonate ions suppressor the ionisation of carbonic acid to help control pH

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How to use curve to determine the value for Ka of acid

Determine pH at 1/2 equivalence point

Ka=10-pH

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Why the order of reaction with respect to iodide ions cannot be 5

The chance of 5 or more ions colliding in rate determining step is negligible

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Why should total volume stay same for every experiment

So the volume of iodate ions is proportional to the concentration

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Explain purpose of starch in reaction mixture

As an indicator

Time taken for formation of blue/ black complex is used to find rate

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Why excess NaOH is used

So all the nitric acid has reacted

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Why is a C=C bond NOT double a C-C bond

C=C bond is weaker than 2 x C-C as it consists of a pi and a sigma bond

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In terms of entropy why is the combustion of prop-2-en-1-ol always feasible in gaseous state

S total is always positive

S surrounding and S system are positive

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Suitable indicator for titration

Phenolphthalein
Pink to colourless
Indicator will change in the verticals region of the graph

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Why is value for Ka of glycolic acid is ten time larger than that of ethanoic acid

The O of the OH group attracts electrons
Stabilises the anion
Weakens O-H Bond in acid so H+ lost more easily

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Maxwell-Boltzmann graph axis

Number of molecule with energy (E)

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Why lowering the temp decreases the rate of reaction

Molecules have lower KE Fewer collisions Fewer successful collisions with energy greater than activation energy

number of electrons in... 1s orbital 2p orbital third quantum shell

1s orbital = 2 2p orbital = 6 third quantum shell = 18

conditions under which magnesium bromide conducts electricity

when molten | when dissolved in water

polarity of P-Cl bond | polarity of phosphorus chloride molecule

polarity of P-Cl bond = polar | polarity of phosphorus chloride molecule = polar

formula and gas/charge ratios of ions responsible for peaks in mass spec of PCl3

P(35Cl)3+ = 136 P(35Cl)2 37Cl+ = 138 P35Cl(37Cl)2+ = 140 P(37Cl)3+ = 142

borax + Hcl = boric acid equation

Na2B4O7.10H20 + 2HCl = 4H3BO3 + 2NaCl + 5H20

O-B-O and B-O-H bond angles in boric acid

O-B-O = 120 B-O-H = 104.5 C

balance _Cl2 + _OH- = _Cl- + _ClO3-+_H2O

3Cl2 + 6OH- = 5Cl- +ClO3- + 3H2O

3Cl2 + 6OH- = 5Cl- +ClO3- + 3H2O why is this a disproportionation reaction

chlorine 0-> -1 so it is reduced | chlorine 0->+5 so it is oxidised

2Mg(NO3)2 = 2MgO + 4NO2 + O2 | why is this a redox reaction

N +5->+4 (reduced) | O -2->0 (oxidised)

calculate x value of Mg(NO3)2.xH2O

``` moles Mg(OH)2 = 0.174/58.3 = 0.00298moles mass Mg(NO3)2 = 0.00298 x 148.3 = 0.44261g 0.765-0.55261 = 0.32239g of water 0.32239/18 = 0.017911 moles /0.00298 = 6 1:6 x=6 ```

which reaction gives negative value for SSystem

A | 2Cu(s)+O2(g)=2CuO(s)

what is the expression fro Stotal

D | Ssystem - H/T

calculate value for free change in energy (G) and show that the decomposition is not feasible at 298K calculate min temp to which calcium carbonate must be heated to make it decompose

``` G= H-(Txsystem) G= 178 - (298 x 165/1000) = +129 Kjmol-1 positive so not feasible T=178/(165/1000) = 1078.8K ```

a buffer solution always .....

D | resists changes in pH if small quantities of acid or base are added

A buffer solution with pH of 3.9 is required. calculate the mass of sodium ethanoate that should be added to 50cm3 of ethnic acid solution of concentration 0.8moldm-3 to form this buffer

``` [H+]=10-3.9 =1.26x10-4 Ka = [H+][A-]/[HA] [A-]=(1.75x10-5)x0.8/(1.26x10-4) = 0.11057 moledm-3 n=cv =0.11057x 50/1000 = 5.5x10-3 mass = n x RFM = 5.5x10-3 x 82 = 0.45g ```

from graph determine activation energy

gradient gradient x 8.31/1000 = +161kjmol-1

reason fro ln k = -7 not being included in line of best fit

anomalous point

solution of glycosidic acid has pH of 2 calculate concentration of this solution Ka= 1.5x10-4moldm-3

``` [H+]=10-2 = 0.01moldm-3 Ka= [H+]2/[HA] [HA]= 0.67 moldm-3 ```

complete equation | CH2OHCOOH + CH3COOH=

CH2OHCOOH + CH3COOH= CH2OHCOO- + CH3COOH2+

What is conc of glycolic acid in Moldm-3

0.125

PH of solution containing just sodium glycolate and water

8.3

water is expected to have lower `bp than hydrogen sulphide but actually has higher BP why?

Lower boiling temp because water has fewer electrons than Hydrogen sulfie Weaker LDF But water also contains Hydrogen bonds HB is stronger than LDF and requires more energy to break

why is water a polar molecule but CO2 isn't ?

Oxygen is more electrongegative than hydrogen and carbon Which results in polar bond with oxygen (d-) so carbon AND hydrogen (d+) CO2 is symmetrical so dipole vecotres cancel Lone pairs of oxygen on water means dipoles do NOT cancel

why is there a larger difference in IE between 2nd and 3rd IE than 1st and 2nd in calcium ?

3rd electron is removed from shell closer to the nucleus | 1st and 2nd are removed from same shell

number of subatomic particle in 18O atom

A 8 protons 10neutrons 8 electrons

mass spec of 79Br and 81Br

total number of electrons in all the occupied p orbital in a chloride ion Cl-

C | 12

which isoelectric ion has largest ionic radius

A | N3-

sub atomic particle in P3- ion

B p = 15 n = 16 e = 18

equation for decomposition of G1 compound sodium nitrate

2NaNO3 = 2NaNO2 + O2

first 3 IE of calcium electrons removed from what orbitals

4s 4s 3p

third IE of calcium equation

Ca2+ (g) = Ca3+ (g) + e-

calculate C-O mean bond enthalpies

+358 Kjmol-1

graph of buffer action

start at pH 3 vertical region at 40cm3 level off at just above pH 12 buffer action at start labelled

deduce order of reaction with respect to iodate ions

first order | straight line through origin

calculate k

k = 394 dm3 mol-1 s-1

enthalpy change of neutralisation

q = mcT H= q/mol -57 kjmol-1

caudate value for enthalpy change of combustion of prop-2-en-1-ol

-1776 kjmol-1

Inorganic 1&2 Flashcards

(63 cards)